Tie1-binding ligands

ABSTRACT

Tie1 is a receptor tyrosine kinase protein that includes a transmembrane domain. Tie1 is present on endothelial cells. This disclosure described antibodies that bind to Tie1, including ones that inhibit endothelial cell activity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 10/916,840, filed on Aug. 12, 2004, which claims priority to U.S. Application Ser. No. 60/494,713, filed on Aug. 12, 2003, the contents of which are hereby incorporated by reference in their entireties.

BACKGROUND

The oxygen and nutrients supplied by the blood vessels are crucial for tissue development and function. Indeed, the cardiovascular system is the first organ system to develop in embryos. During organogenesis and the development tissues or tumors, the proximity of the growing cells to the circulatory system is ensured by the coordinated growth of blood vessels and organ parenchyma. It may be possible to prevent or treat diseases by modulating blood vessel development or angiogenesis.

Blood vessels are composed of an inner layer of endothelial cells and an outer layer of pericytes or smooth muscle cells. The first tubular structures are formed by endothelial cells that subsequently recruit pericytes and smooth muscle cells to ensheath them. The de novo formation of blood vessels from a dispersed population of mesodermally derived endothelial precursor cells is termed vasculogenesis. This primitive network undergoes successive morphogenetic events including sprouting, splitting and remodeling to generate the hierarchical vascular network from large to branched small vessels. These successive morphogenetic events are collectively called angiogenesis. Previous studies have identified a number of endothelial cell specific receptor tyrosine kinases (RTKs) and their cognate ligands, which mediate the vasculogenic and angiogenic development of blood vessels. Members of the vascular endothelial growth factor (VEGF) family and their receptors function during the formation of the initial embryonic vascular plexus, whereas angiopoietins (Angs) and their receptor, Tie2, as well as ephrins and their Eph receptors are implicated in the subsequent remodeling processes. See, e.g., Jones et al. (2001) Nature Reviews 2:257 for a review of receptors involved in angiogenic and lymphangiogenic responses.

Tie1 and Tie2 are RTKs that are expressed almost exclusively in endothelial cells and hematopoietic precursor cells. These two receptors are required for the normal development of vascular structures during embryogenesis. The two Tie receptors form a RTK subfamily since, unlike other RKT family members, they include extracellular EGF-homology domains. See, e.g., Partanen (1992) Mol Cell Biol 12:1698 and WO 93/14124. Targeted disruption of the Tie1 gene in mice results in a lethal phenotype characterized by extensive hemorrhage and defective microvessel integrity. See, e.g., Puri et al. (1995) EMBO J. 14:5884. Tie2 null embryos have defects in vascular remodeling and maturation, resulting from improper recruitment of periendothelial supporting cells. At least three ligands, designated the angiopoietins (Ang), have been identified for Tie2, while the ligands for Tie1 are still unknown. Mice lacking Ang1 show defects in vascular development, which are reminiscent of but slightly less severe than those of mice lacking Tie2. Binding of Ang1 induces tyrosine phosphorylation of Tie2 and activation of its signaling pathways, but Ang2 has been reported to antagonize these effects in endothelial cells. Accordingly, transgenic overexpression of Ang2 disrupts blood vessels formation in mouse embryos. So far, four angiopoietins and many related proteins have been discovered, although none of them appears to binds Tie1.

SUMMARY

In one aspect, the invention features a protein (e.g., an isolated protein) that includes a heavy chain immunoglobulin variable domain sequence and a light chain immunoglobulin variable domain sequence. The protein ligand binds to Tie1 ectodomain. For example, the protein binds with an affinity K_(D) of less than 10⁻⁸ M, 5·10⁻⁹ M, 10⁻⁹ M, 10⁻¹⁰ M, 10⁻¹¹ M, or 10⁻¹² M.

In one embodiment, one or more of the CDRs of the heavy and/or light chain variable domain sequence are human, primate, non-rodent (e.g., non-mouse or non-rat), or synthetic. In one embodiment, one or more of the framework regions of the heavy and/or light chain variable domain sequence are human, primate, or non-rodent (e.g., non-mouse or non-rat).

In one embodiment, the heavy chain includes one or more of the following properties:

i) a HC CDR1 that includes an amino acid sequence as follows:

(AGSR)-Y-(GVK)-M-(GSVF), (SEQ ID NO:117)

(AGSIMRH)-Y-(GVMK)-M-(GSVMFH) (SEQ ID NO:118), or

(AGSIMRNH)-Y-(AGTVMKPQ)-M-(AGSTVMYWFKH) (SEQ ID NO:119);

ii) a HC CDR2 that includes an amino acid sequence as follows:

X-I-Y-P-S-G-G-X-T-X-Y-A-D-S-V-K-G (SEQ ID NO:120), wherein X is any amino acid,

-   -   (GSV)-I-(SY)-P-S-G-G-(WQ)-T-(GY) (SEQ ID NO:121),     -   (GSV)-I-(SY)-P-S-G-G-(WNQ)-T-(GY) (SEQ ID NO:160)     -   (GSV)-I-(SY)-P-S-G-G-(WQ)-T-(GY)-Y-A-D-S-V-K-G (SEQ ID NO:122),         or     -   (GSVW)-I-(SY)-P-S-G-G-(AGVMYWPQH)-T-(AGSTLVMYFKH) (SEQ ID         NO:123);

iii) a HC CDR3 that includes an amino acid sequence as follows:

V-(four or five residues)-F-D-(I/Y) (SEQ ID NO:124),

G-Y-G-P-I-A-P-G-L-D-Y (SEQ ID NO:125),

(GV)-N-Y-Y-(GYD)-S-(SD)-G-Y-G-P-I-A-P-G-L-D-Y (SEQ ID NO:126),

(GVD)-(AGLN)-(LYR)-(GSTLYH)-(GYD)-(AGSYFP)-(SFD)-(AGYD)-(IY)-(GFD)-(YDP)-(IP)-A-P-G-L-D-Y (SEQ ID NO:127), or

VNYYDSSGYGPIAPGLDY (SEQ ID NO:128).

In one embodiment, the light chain includes one or more of the following properties:

i) a LC CDR1 that includes an amino acid sequence as follows:

R-A-S-Q-S-(IV)-S-(SR)-X1-Y-L-(AN) (SEQ ID NO:129),

R-A-S-Q-S-V-S-S-X-L (SEQ ID NO:130),

R-A-S-Q-S-(IV)-S-(SR)-(SY)-(LY)-(ALN) (SEQ ID NO:131), or

R-A-S-(REQ)-(GSTRN)-(IV)-(GSTIRN)-(STIRH)-X1-(SYWNH)-(LV)-(ASN) (SEQ ID NO:132), wherein X1 can be serine or absent;

ii) a LC CDR2 that includes an amino acid sequence as follows:

X-A-S-X-R-A-T (SEQ ID NO:133), wherein X can be any amino acid,

(AGD)-A-S-(STN)-R-A-T (SEQ ID NO:134),

(AGD)-A-S-(STN)-(LR)-(AEQ)-(ST) (SEQ ID NO:135), or

(AGTKDEH)-A-S-(STN)-(LR)-(AVEQ)-(ST) (SEQ ID NO:136); and

iii) a LC CDR3 that includes an amino acid sequence as follows:

Q-Q-(SYFR)-(GSYN)-S-(STYW)-(RP)-(LWRH)-(TIY) (SEQ ID NO:161),

Q-Q-(SYFR)-(GSYN)-S-(STYW)-(RP)-(LWR)-(TIY)-T (SEQ ID NO:137),

(LQ)-Q-(SYFR)-(GSYN)-(SKN)-(STYW)-(RP)-(LWR)-(TIY)-T (SEQ ID NO:138),

Q-Q-(YR)-(GS)-S-(SW)-P-R-X1-T (SEQ ID NO:139), wherein X1 is any amino acid or absent,

(LQ)-(LQ)-(SYFRD)-(GSYN)-(STRKN)-(STYWF)-(RP)-(ILMWRH)-(TIY)-(TI) (SEQ ID NO:140), or

(LQ)-(LRQ)-(SYFRD)-(GSYN)-(ASTRKN)-(STYWF)-(SVRP)-(STILMWRH)-(TIY)-(STI) (SEQ ID NO:141).

In one embodiment, the light chain includes one or more of the following properties:

i) a LC CDR1 that includes an amino acid sequence as follows:

S-X-(ND)-(IV)-(AG)-X1-X2-X3 (SEQ ID NO:142), or

T-(GR)-(ST)-S-X5-(ND)-(IV)-(AG)-X1-X2-X3-Y-X4-S (SEQ ID NO:143), wherein X1 is any amino acid (e.g., G or R), X2 is any amino acid (e.g., Y or N), X3 is any amino acid (e.g., F, N, or K), X4 is any amino acid (e.g., aliphatic, e.g., V or A);

ii) a LC CDR2 that includes an amino acid sequence as follows:

(DE)-V-N-N-R-P-S (SEQ ID NO:144)

(DE)-(VD)-(STDN)-(YRDN)-R-P-S (SEQ ID NO:145);

iii) a LC CDR3 that includes an amino acid sequence as follows:

(SQ)-S-(SY)-(ASID)-(GSR)-(ST)-(STRN)-(STYR)-(ATLY)-(SVWQ) (SEQ ID NO:146)

In one embodiment, the HC CDR2 includes an amino acid sequence as follows: (GSVW)-I-(SY)-P-SG-G-(AGVMYWPQH)-T-(AGSTLVMYFKH)-Y-(AT)-D-S-V-K-G (SEQ ID NO:147) or (GSV)-I-(SY)-P-SG-G-(WQ)-T-(GY)-Y-(AT)-D-S-V-K-G (SEQ ID NO:148).

In one embodiment, the protein includes HC CDR1 and HC CDR2 sequences that are related to the corresponding CDR sequences of p-F3 and E3. For example, the protein includes the sequence MYGM (SEQ ID NO:149), at a position corresponding to HC CDR1. The sequence can be followed by a small amino acid, e.g., glycine, alanine, valine, or serine. In another example, the protein the sequence VISPSGGX₁TX₂YADSAVKG (SEQ ID NO:150), at a position corresponding to HC CDR2. For example, X₁ can be a hydrophilic amino acid, e.g., glutamine or asparagine. For example, X₂ can be a small amino acid, e.g., glycine, alanine, valine, or serine.

In one embodiment, two or three of the CDRs of the HC variable domain sequence match motifs that also match a HC variable domain of an antibody described herein. Similarly, in one embodiment, two or three of the CDRs of the LC variable domain sequence match motifs that also match a LC variable domain of an antibody described herein. In still another embodiment, the matched motifs for the CDRs are based on a HC and a LC that are paired in an antibody described herein.

In one embodiment, the H1 and H2 hypervariable loops have the same canonical structure as an antibody described herein. In one embodiment, the L1 and L2 hypervariable loops have the same canonical structure as an antibody described herein.

In one embodiment, the HC CDR1 amino acid sequences have a length of at least 5 amino acids of which at least 3, 4, or 5 amino acids are identical to the CDR1 sequence of the HC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. In one embodiment, the HC CDR2 amino acid sequences have a length of at least 15, 16, or 17 amino acids of which at least 10, 12, 14, 15, 16, or 17 amino acids are identical to the CDR2 sequence of the HC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. In one embodiment, the HC CDR2 amino acid sequences have a length of at least 17 amino acids of which at least 14, 15, 16, or 17 amino acids are identical to the CDR2 sequence of the HC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. In one embodiment, the HC CDR3 amino acid sequences have a length of at least of at least 7 or 8 amino acids of which at least 5, 6, 7, or 8 amino acids are identical to the CDR3 sequence of the HC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

In one embodiment, two or three of the CDRs of the HC variable domain sequence match motifs described herein such that the motifs are a set of motifs that match a HC variable domain of a clone described herein, e.g., E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. For example, the protein may include SEQ ID NO:118 and SEQ ID NO:160, e.g., motifs that match the E3 HC variable domain.

In one embodiment, the LC CDR1 amino acid sequences have a length of at least 10, 11, or 12 amino acids of which at least 7, 8, 9, 10, or 11 amino acids are identical to the CDR1 sequence of the LC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. In one embodiment, the LC CDR2 amino acid sequences have a length of at least 6 or 7 amino acids of which at least 5, 6, or 7 amino acids are identical to the CDR2 sequence of the LC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. In one embodiment, the LC CDR3 amino acid sequences have a length of at least of at least 8, 9, or 10 amino acids of which at least 7, 8, 9, or 10 amino acids are identical to the CDR3 sequence of the LC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

In one embodiment, two or three of the CDRs of the LC variable domain sequence match motifs described herein such that the motifs are a set of motifs that match a LC variable domain of a clone described herein, e.g., E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. For example, the protein may include SEQ ID NO:132, SEQ ID NO:136, and SEQ ID NO:161, e.g., motifs that match the E3 LC variable domain.

In one embodiment, the amino acid sequence of the HC variable domain sequence is at least 70, 80, 85, 90, 92, 95, 97, 98, 99, or 100% identical to the amino acid sequence of the HC variable domain of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

In one embodiment, the amino acid sequence of the LC variable domain sequence is at least 70, 80, 85, 90, 92, 95, 97, 98, 99, or 100% identical to the amino acid sequence of the LC variable domain of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

In one embodiment, the amino acid sequences of the HC and LC variable domain sequences are at least 70, 80, 85, 90, 92, 95, 97, 98, 99, or 100% identical to the amino acid sequences of the HC and LC variable domains of a clone selected from the group consisting of E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, and s-H4.

In one embodiment, the amino acid sequences of one or more framework regions (e.g., FR1, FR2, FR3, and/or FR4) of the HC and/or LC variable domain are at least 70, 80, 85, 90, 92, 95, 97, 98, 99, or 100% identical to corresponding framework regions of the HC and LC variable domains of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

In one embodiment, the light chain variable domain sequence is human or non-immunogenic in a human. In one embodiment, the heavy chain variable domain sequence is human or non-immunogenic in a human.

The protein can bind to cells that express Tie1, e.g., endothelial cells. In one embodiment, the protein does not substantially bind (e.g., does not detectably bind) to platelets (e.g., resting and/or activated platelets).

In one embodiment, the protein inhibits tube formation by HUVECs in vitro.

In one embodiment, the protein recognizes melanoma-associated structures in a histological section, e.g., not only melanoma tissue, but antigen in surrounding structures. In one embodiment, the protein does not stain blood vessels in normal skin in a histological section.

In one embodiment, the protein specifically binds to Tie1, e.g., it binds with at least a 10, 50, 100, 10³, or 10⁴ fold preference for Tie1 relative to another human protein, e.g., Tie2, a natural protein other than Tie1 that has a Ig-like domain, an EGF-like domain, or fibronectin Type III repeat, or human serum albumin. In one embodiment, the protein binds to a domain of Tie1 described herein.

In another aspect, the invention features a protein (e.g., an isolated protein) that modulates activity of Tie1, e.g., the Tie1 receptor. For example, the protein is not naturally occurring. In one embodiment, the protein includes a HC and LC immunoglobulin variable domain sequence. In one embodiment, one or more of the CDRs of the heavy and/or light chain variable domain sequence are human, primate, non-rodent (e.g., non-mouse or non-rat), or synthetic. In one embodiment, one or more of the framework regions of the heavy and/or light chain variable domain sequence are human, primate, or non-rodent (e.g., non-mouse or non-rat). In another embodiment, the protein is substantially free of an immunoglobulin variable domain, e.g., the protein includes a peptide that independently interacts with Tie1.

In one embodiment, the protein activates an activity of the Tie1 protein.

In one embodiment, the protein includes the HC and LC immunoglobulin variable domains of the E3 antibody or domains that are at least 70, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100% identical in the CDR regions. In one embodiment, the protein competes with E3 for binding to Tie1 or binds to an epitope that overlaps an epitope that is recognized by E3 or that has at least one, two or three residues in common with an epitope that is recognized by E3.

In one embodiment, the activating protein enables IL-3 dependent cells that express a chimeric receptor including the Tie1 extracellular domain and the EpoR intracellular domain to survive in the absence of IL-3.

In one embodiment, the protein can cause dimerization of Tie1. In one embodiment, the protein can cause auto-phosphorylation of the RTK domain of Tie1.

In one embodiment, the protein synergizes with the E3 antibody to activate an activity of Tie. In one embodiment, the protein includes the HC and LC immunoglobulin variable domains of the G2 or C7 antibody or domains that are at least 70, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100% identical in the CDR regions. In one embodiment, the protein competes with G2 or C7 for binding to Tie1 or binds to an epitope that overlaps an epitope that is recognized by G2 or C7 or that has at least one, two or three residues in common with an epitope that is recognized by G2 or C7.

In another embodiment, the protein antagonizes an activity of the Tie1 protein. For example, the protein can at least partially inhibit the ability of the E3 antibody to agonize the Tie protein. In one embodiment, the protein can at least partially inhibit the ability of the E3 antibody to enable IL-3 dependent cells that express a chimeric receptor including the Tie1 extracellular domain and the EpoR intracellular domain to survive in the absence of IL-3.

In one embodiment, the HC and LC immunoglobulin variable domains of the protein include the amino acid sequences that are at least 70, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100% identical to the amino acid sequences of respective immunoglobulin variable domains of B2 or D11.

In one embodiment, the Tie1 modulator protein includes the HC and LC immunoglobulin variable domains of an antibody selected from the group consisting of: B2, D11, A2, A10, P-B1, P-B3, and P-C6 or immunoglobulin domains that are at least 70, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100% identical in the CDR regions to the CDR regions of the respective antibodies. For example, the protein binds with an affinity K_(D) of less than 10⁻⁸ M, 5·10⁻⁹ M, 10⁻⁹ M, 10⁻¹⁰M, 10⁻¹¹ M, or 10⁻¹² M.

In one embodiment, the protein can at least partially inhibit the ability of a naturally occurring Tie1 binding protein from interacting with the Tie protein.

The protein can include other features described herein.

In another aspect, the invention features an antibody (e.g., an isolated antibody) that binds to the Tie1 ectodomain, but does not substantially bind to platelets, e.g., as detected by fluorescence activated cell sorting. For example, the antibody does not substantially bind to activated platelets and/or resting platelets. In one embodiment, the antibody binds to endothelial cells. In one embodiment, the protein is a monoclonal antibody. The antibody can be provided in a preparation that is free of other Tie1-binding antibodies that have other specificities, e.g., free of Tie1 binding antibodies that bind to platelets. The antibody can include other features described herein.

In another aspect, the invention features a protein (e.g., an isolated protein) that preferentially binds to a Tie1 protein in a conformation stabilized by the E3 antibody relative to an endogenous Tie1 protein in an unstimulated state. In one embodiment, the protein includes immunoglobulin HC and LC domains. In another embodiment, the protein includes a peptide (e.g., of length less than 30, 28, 25, 22, 20, 18, 16, or 14 amino acids) that independently binds to Tie1. For example, the peptide can include one, two, or three disulfide bonds. The protein can include other features described herein.

In another aspect, the invention features a protein (e.g., an isolated protein) that preferentially binds to a Tie1 protein in a dimeric conformation relative to a monomeric Tie1 protein. In one embodiment, the protein includes immunoglobulin HC and LC domains. In another embodiment, the protein includes a peptide (e.g., of length less than 30, 28, 25, 22, 20, 18, 16, or 14 amino acids) that independently binds to Tie1. For example, the peptide can include one, two, or three disulfide bonds. The protein can include other features described herein.

In another aspect, the invention features a protein (e.g., an isolated protein) that binds to an epitope of Tie1 ectodomain with a K_(D) of less than 2×10⁻⁷ M. The epitope overlaps, is within, or includes an epitope bound by E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4 or that includes at least one, two, or three residues in common. For example, the protein binds with an affinity K_(D) of less than 10⁻⁸ M, 5·10⁻⁹ M, 10⁻⁹ M, 10⁻¹⁰ M, 10⁻¹¹ M, or 10⁻¹² M. In one embodiment, the protein includes immunoglobulin HC and LC domains. In another embodiment, the protein includes a peptide (e.g., of length less than 30, 28, 25, 22, 20, 18, 16, or 14 amino acids) that independently binds to Tie1. For example, the peptide can include one, two, or three disulfide bonds. The protein can include other features described herein.

In another aspect, the invention features a protein (e.g., an isolated protein) that competitively inhibits binding of E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4 to a Tie1 ectodomain. In one embodiment, the protein includes immunoglobulin HC and LC domains. In another embodiment, the protein includes a peptide (e.g., of length less than 30, 28, 25, 22, 20, 18, 16, or 14 amino acids) that independently binds to Tie1. For example, the peptide can include one, two, or three disulfide bonds. The protein can include other features described herein.

In another aspect, the invention features a protein (e.g., an isolated protein) that includes a heavy chain immunoglobulin variable domain and a light chain immunoglobulin variable domain and that antagonizes an activity of the Tie1 ectodomain. In one embodiment, CDR1 of the light chain variable domain includes: Q-S-X-S-S (SEQ ID NO:151) or R-A-S-Q-S-X-S-S-Y-L-A (SEQ ID NO:152), wherein X is any amino acid or optionally aliphatic, e.g., isoleucine or valine. In one embodiment, CDR2 of the light chain variable domain includes: A-S-X₁-R-X₂-T (SEQ ID NO:153) or D-A-S-X₁-R-X₂-T (SEQ ID NO:154), wherein X₁ is any amino acid or optionally a hydrophilic amino acid, e.g., serine or asparagine, and X₂ is any amino acid or optionally aliphatic or small aliphatic, e.g., alanine or valine. In one embodiment, CDR3 of the light chain variable domain includes: Q-R-S-X₂-W-P-R (SEQ ID NO:155) or X₁-Q-R-S-X₂-W-P-R-T (SEQ ID NO:156), wherein X₁ is any amino acid or optionally leucine or glutamine, and X₂ is any amino acid or optionally lysine or serine.

In one embodiment, the protein competes with the B2 and/or D11 antibody for binding to Tie1 or competitively inhibits binding of B2 and/or D11 to Tie1.

In one embodiment, the protein antagonizes a Tie1 activity that is stimulated by the E3 antibody. In one embodiment, the protein inhibits dimerization of Tie1. The protein can include other features described herein.

In another aspect, the invention features an isolated, mono-specific protein including a heavy chain immunoglobulin variable domain sequence and a light chain immunoglobulin variable domain sequence, wherein the protein binds to Tie1 ectodomain and includes a human or non-mouse constant domain (e.g., a human IgG1, 2, 3, or 4 constant domain. The protein can include other features described herein.

In another aspect, the invention features an isolated, human antibody that binds to a Tie1 ectodomain. The protein can include other features described herein.

In another aspect, the invention features an isolated antibody (e.g., an isolated antibody) that binds to a Tie1 ectodomain and contains less than 5, 4, 3, or 2 peptides (of between 6-9 amino acid length) that are non-human in origin or less than 5, 4, 3, or 2 peptides that are potential human T cell epitopes. In one embodiment, the antibody contains no peptide (of 6-9 amino acid length) that is non-human in origin or that is a potential human T cell epitope.

In one embodiment, the antibody is obtained by a method that includes deimmunization. For example, the antibody is deimmunized, e.g., completely deimmunized. The protein can include other features described herein.

In another aspect, the invention features an isolated antibody that binds to a Tie1 ectodomain and that includes a modified Fc domain, e.g., a modified human Fc domain. For example, antibodies may include modifications, e.g., that alter Fc function. For example, the human IgG1 constant region can be mutated at one or more residues, e.g., one or more of residues 234 and 237, e.g., according to the number in U.S. Pat. No. 5,648,260. Other exemplary modifications include those described in U.S. Pat. No. 5,648,260. The protein can include other features described herein.

In another aspect, the invention features an isolated protein that binds to the Tie1 receptor with an affinity K_(D) of less than 10⁻⁷ M, 10⁻⁸ M, 5·10⁻⁹ M, 10⁻⁹ M, 10⁻¹⁰ M, 10⁻¹¹ M, or 10⁻¹² M. The protein can include other features described herein.

In another aspect, the invention features an isolated protein including a heavy chain immunoglobulin variable domain sequence and a light chain immunoglobulin variable domain sequence, wherein the protein binds to Tie1 ectodomain and, for example, includes at least one or more CDR's that are a non-primate CDR (e.g., a non-mouse or non-rabbit CDR) or a synthetic CDR. The protein can include other features described herein.

In another aspect, the invention features an isolated nucleic acid including a coding sequence that encodes a polypeptide including an immunoglobulin HC variable domain of an antigen binding protein that binds to Tie1. In one embodiment, the HC variable domain includes one or more of the following properties

i) a HC CDR1 that includes an amino acid sequence as follows:

(AGSR)-Y-(GVK)-M-(GSVF) (SEQ ID NO:117),

(AGSIMRH)-Y-(GVMK)-M-(GSVMFH) (SEQ ID NO:118), or

(AGSIMRNH)-Y-(AGTVMKPQ)-M-(AGSTVMYWFKH) (SEQ ID NO:119);

ii) a HC CDR2 that includes an amino acid sequence as follows:

X-I-Y-P-S-G-G-X-T-X-Y-A-D-S-V-K-G (SEQ ID NO:120), wherein X is any amino acid,

(GSV)-I-(SY)-P-S-G-G-(WQ)-T-(GY) (SEQ ID NO:121),

(GSV)-I-(SY)-P-S-G-G-(WQ)-T-(GY)-Y-A-D-S-V-K-G (SEQ ID NO:122), or

(GSVW)-I-(SY)-P-S-G-G-(AGVMYWPQH)-T-(AGSTLVMYFKH) (SEQ ID NO:123);

iii) a HC CDR3 that includes an amino acid sequence as follows:

V-(four or five residues)-F-D-(I/Y) (SEQ ID NO:124),

G-Y-G-P-I-A-P-G-L-D-Y (SEQ ID NO:125),

(GV)-N-Y-Y-(GYD)-S-(SD)-G-Y-G-P-I-A-P-G-L-D-Y (SEQ ID NO:126),

(GVD)-(AGLN)-(LYR)-(GSTLYH)-(GYD)-(AGSYFP)-(SFD)-(AGYD)-(IY)-(GFD)-(YDP)-(IP)-A-P-G-L-D-Y (SEQ ID NO:127), or

VNYYDSSGYGPIAPGLDY (SEQ ID NO:128).

In one embodiment, the HC CDR1 amino acid sequences have a length of at least 5 amino acids of which at least 3, 4, or 5 amino acids are identical to the CDR1 sequence of the HC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. In one embodiment, the HC CDR2 amino acid sequences have a length of at least 15, 16, or 17 amino acids of which at least 10, 12, 14, 15, 16, or 17 amino acids are identical to the CDR2 sequence of the HC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. In one embodiment, the HC CDR2 amino acid sequences have a length of at least 17 amino acids of which at least 14, 15, 16, or 17 amino acids are identical to the CDR2 sequence of the HC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. In one embodiment, the HC CDR3 amino acid sequences have a length of at least of at least 7 or 8 amino acids of which at least 5, 6, 7, or 8 amino acids are identical to the CDR3 sequence of the HC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

In one embodiment, two or three of the CDRs of the HC variable domain sequence match motifs described herein such that the motifs are a set of motifs that match a HC variable domain of a clone described herein, e.g., E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

In one embodiment, the amino acid sequence of the HC variable domain sequence is at least 70, 80, 85, 90, 92, 95, 97, 98, 99, or 100% identical to the amino acid sequence of the HC variable domain of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

In one embodiment, the nucleic acid further includes a second coding sequence that encodes a polypeptide including an immunoglobulin LC variable domain, e.g., a LC domain described herein. In one embodiment, the nucleic acid further includes a promoter operably linked to the coding sequence.

In another aspect, the invention features an isolated nucleic acid including a coding sequence that encodes a polypeptide including an immunoglobulin LC variable domain of an antigen binding protein that binds to Tie1. In one embodiment, the LC variable domain includes one or more of the following properties: i) a LC CDR1 that includes an amino acid sequence as follows:

R-A-S-Q-S-(IV)-S-(SR)-X1-Y-L-(AN) (SEQ ID NO:129),

R-A-S-Q-S-V-S-S-X-L (SEQ ID NO:130),

R-A-S-Q-S-(IV)-S-(SR)-(SY)-(LY)-(ALN) (SEQ ID NO:131), or

R-A-S-(REQ)-(GSTRN)-(IV)-(GSTIRN)-(STIRH)-X1-(SYWNH)-(LV)-(ASN) (SEQ ID NO:132), wherein X1 can be serine or absent;

ii) a LC CDR2 that includes an amino acid sequence as follows:

X-A-S-X-R-A-T (SEQ ID NO:133), wherein X can be any amino acid,

(AGD)-A-S-(STN)-R-A-T (SEQ ID NO:134),

(AGD)-A-S-(STN)-(LR)-(AEQ)-(ST) (SEQ ID NO:135), or

(AGTKDEH)-A-S-(STN)-(LR)-(AVEQ)-(ST) (SEQ ID NO:136); and

iii) a LC CDR3 that includes an amino acid sequence as follows:

Q-Q-(SYFR)-(GSYN)-S-(STYW)-(RP)-(LWR)-(TIY)-T (SEQ ID NO:137),

(LQ)-Q-(SYFR)-(GSYN)-(SKN)-(STYW)-(RP)-(LWR)-(TIY)-T (SEQ ID NO:138),

Q-Q-(YR)-(GS)-S-(SW)-P-R-X1-T (SEQ ID NO:139), wherein X1 is any amino acid or absent,

(LQ)-(LQ)-(SYFRD)-(GSYN)-(STRKN)-(STYWF)-(RP)-(ILMWRH)-(TIY)-(TI) (SEQ ID NO:140), or

(LQ)-(LRQ)-(SYFRD)-(GSYN)-(ASTRKN)-(STYWF)-(SVRP)-(STILMWRH)-(TIY)-(STI) (SEQ ID NO:141); and

In one embodiment, the light chain includes one or more of the following properties:

i) a LC CDR1 that includes an amino acid sequence as follows:

S-X-(ND)-(IV)-(AG)-X1-X2-X3 (SEQ ID NO:142), or

T-(GR)-(ST)-S-X5-(ND)-(IV)-(AG)-X1-X2-X3-Y-X4-S (SEQ ID NO:143), wherein X1 is any amino acid (e.g., G or R), X2 is any amino acid (e.g., Y or N), X3 is any amino acid (e.g., F, N, or K), X4 is any amino acid (e.g., aliphatic, e.g., V or A);

iii) a LC CDR2 that includes an amino acid sequence as follows:

(DE)-V-N-N-R-P-S (SEQ ID NO:144)

(DE)-(VD)-(STDN)-(YRDN)-R-P-S (SEQ ID NO:145);

v) a LC CDR3 that includes an amino acid sequence as follows:

-   -   (SQ)-S-(SY)-(ASID)-(GSR)-(ST)-(STRN)-(STYR)-(ATLY)-(SVWQ) (SEQ         ID NO:146)

In one embodiment, the HC CDR2 includes an amino acid sequence as follows: (GSVW)-I-(SY)-P-SG-G-(AGVMYWPQH)-T-(AGSTLVMYFKH)-Y-(AT)-D-S-V-K-G (SEQ ID NO:147) or (GSV)-I-(SY)-P-SG-G-(WQ)-T-(GY)-Y-(AT)-D-S-V-K-G (SEQ ID NO:148).

In one embodiment, CDR1 of the light chain variable domain includes: Q-S-X-S-S (SEQ ID NO:151) or R-A-S-Q-S-X-S-S-Y-L-A (SEQ ID NO:152), wherein X is any amino acid or optionally aliphatic, e.g., isoleucine or valine. In one embodiment, CDR2 of the light chain variable domain includes: A-S-X₁-R-X₂-T (SEQ ID NO:153) or D-A-S-X₁-R-X₂-T (SEQ ID NO:154), wherein X₁ is any amino acid or optionally a hydrophilic amino acid, e.g., serine or asparagine, and X₂ is any amino acid or optionally aliphatic or small aliphatic, e.g., alanine or valine. In one embodiment, CDR3 of the light chain variable domain includes: Q-R-S-X₂-W-P-R (SEQ ID NO:155) or X₁-Q-R-S-X₂-W-P-R-T (SEQ ID NO:156), wherein X₁ is any amino acid or optionally leucine or glutamine, and X₂ is any amino acid or optionally lysine or serine.

In one embodiment, the LC CDR1 amino acid sequences have a length of at least 10, 11, or 12 amino acids of which at least 7, 8, 9, 10, or 11 amino acids are identical to the CDR1 sequence of the LC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. In one embodiment, the LC CDR2 amino acid sequences have a length of at least 6 or 7 amino acids of which at least 5, 6, or 7 amino acids are identical to the CDR2 sequence of the LC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. In one embodiment, the LC CDR3 amino acid sequences have a length of at least of at least 8, 9, or 10 amino acids of which at least 7, 8, 9, or 10 amino acids are identical to the CDR3 sequence of the LC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

In one embodiment, the amino acid sequence of the LC variable domain sequence is at least 70, 80, 85, 90, 92, 95, 97, 98, 99, or 100% identical to the amino acid sequence of the LC variable domain of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

In one embodiment, the nucleic acid further includes a second coding sequence that encodes a polypeptide including an immunoglobulin HC variable domain, e.g., an HC domain described herein. In one embodiment, the nucleic acid further includes a promoter operably linked to the coding sequence.

In another aspect, the invention features a nucleic acid that includes one or more coding sequence that encodes one or more polypeptide chains that collectively include an immunoglobulin HC or LC variable domain of an antigen binding protein that binds to Tie1. In one embodiment, the nucleic acid segment encoding at least one of the variable domains hybridizes to a nucleic acid described herein, e.g., under stringent conditions (e.g., high stringency conditions). The nucleic acid can include other features described herein.

In another aspect, the invention features a host cell that contains a first nucleic acid sequence encoding a polypeptide including a HC variable domain of an antigen binding protein and a second nucleic acid sequence encoding a polypeptide including a LC variable domain of the antigen binding protein, wherein the antigen binding protein binds to Tie1 with a K_(D) of less than 2×10⁻⁷ M. In one embodiment, the HC or LC variable domain includes at least one human CDR. The antigen binding protein can include other features described herein.

In another aspect, the invention features a host cell that contains a first nucleic acid encoding a polypeptide including a HC variable region and a second nucleic acid encoding a polypeptide including a LC variable region, wherein the HC and the LC variable regions each include at least 70, 80, 85, 90, 92, 95, 97, 98, 99, or 100% identical to respective amino acid sequences of the HC and LC variable domains of a clone selected from the group consisting of E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, and s-H4. The antigen binding protein can include other features described herein.

In another aspect, the invention features a pharmaceutical composition including a protein described herein that interacts with Tie1 and a pharmaceutically acceptable carrier.

In another aspect, the invention features a therapeutic composition including a protein described herein that interacts with Tie1 wherein the composition is sterile and suitable for administration to a subject.

In another aspect, the invention features a method that includes: providing a signal-dependent or signal-responsive cell that expresses a chimeric receptor including the Tie1 extracellular domain and a heterologous intracellular sequence that can produce a signal; contacting a candidate compound to the cell; and evaluating a property of the cell that is dependent on the signal. In one embodiment, the intracellular sequence includes at least a region of an intracellular sequence of the EpoR protein. The method can be used, e.g., to evaluate activity of a candidate compound, or a plurality of compounds.

In another aspect, the invention features a method that includes: providing an IL-3 dependent cell that expresses a chimeric receptor including the Tie1 extracellular domain and the EpoR intracellular domain; contacting a candidate compound to the cell under conditions in which the concentration of IL-3 is not sufficient to sustain viability of the cell; and evaluating a property of the cell. The method can be used, e.g., to evaluate activity of a candidate compound, or a plurality of compounds. In one embodiment, the property is viability. In one embodiment, the evaluating includes an MTT assay. In one embodiment, the method further includes administering the candidate compound to a subject. For example, the candidate compound includes a protein, e.g., a protein that includes an immunoglobulin variable domain.

In another aspect, the invention features method of identifying a compound that modulates Tie1 activity. The method includes: providing a plurality of candidate compounds; and evaluating each compound of the plurality using a method described herein.

In another aspect, the invention features a culture cell that expresses a chimeric transmembrane protein including a region of the Tie1 extracellular domain and a heterologous intracellular sequence. In one embodiment, the intracellular sequence includes a region of the EpoR intracellular domain. In one embodiment, the cell requires IL-3 or Tie1 for viability. For example, the cell is IL-3 dependent in the absence of the chimeric transmembrane protein, but is viable in the presence of the E3 antibody and the absence of IL-3.

In another aspect, the invention features a preparation that includes the isolated mammalian cells (e.g., cells that expresses a chimeric transmembrane protein including a region of the Tie1 extracellular domain and a heterologous intracellular sequence) and a Tie1-binding ligand, wherein the Tie1-binding ligand is necessary to sustain viability of the cells.

In another aspect, the invention features a kit including: a Tie1-binding ligand and a culture cell that expresses a chimeric transmembrane protein including a region of the Tie1 extracellular domain and a heterologous intracellular sequence.

In another aspect, the invention features a method of evaluating a candidate compound. The method includes: providing a preparation that includes (i) a cell or membrane fraction that contains (a) an insoluble protein that includes a region of the Tie1 extracellular domain and a kinase domain and (b) ATP; (ii) a ligand that causes alters activity of the kinase domain; and (iii) the candidate compound; and evaluating phosphorylation state of the insoluble protein.

In another aspect, the invention features a method of evaluating a candidate compound. The method includes: providing a preparation that includes (i) a cell or membrane fraction that includes a Tie1 protein or a transmembrane protein that includes at least a region of the Tie1 extracellular domain and ATP; (ii) a ligand that causes autophosphorylation of Tie1 or the transmembrane protein; and (iii) the candidate compound; and evaluating phosphorylation state of the Tie1 protein.

In one embodiment, the ligand is an antibody. In one embodiment, the ligand includes the HC and LC immunoglobulin variable domains of the E3 antibody or domains that are at least 90% identical in the CDR regions. In one embodiment, the method further includes administering the candidate compound to a subject.

In another aspect, the invention features a method that includes: providing a preparation that includes (i) a cell or membrane fraction that includes a transmembrane protein that includes at least a region of the Tie1 extracellular domain and ATP; and (ii) a ligand that causes autophosphorylation of Tie1 or the transmembrane protein; and evaluating phosphorylation state of the transmembrane protein.

In another aspect, the invention features a method that includes: contacting a mammalian cell with a ligand that (i) can agonize Tie1 autophosphorylation and/or (ii) can enable an IL-3 dependent cell that expresses a chimeric receptor including the Tie1 extracellular domain and the EpoR intracellular domain to remain viable under conditions in which the concentration of IL-3 is not sufficient to sustain viability of the cell; and evaluating the mammalian cell. In one embodiment, the cell expresses an endogenous Tie1 protein. In one embodiment, the cell is an endothelial cell. In one embodiment, the method further includes contacting the mammalian cell with a test compound, other than the ligand. For example, the ligand is an antibody. For example, the ligand includes the HC and LC immunoglobulin variable domains of the E3 antibody or domains that are at least 90% identical in the CDR regions.

In another aspect, the invention features a method that includes: contacting a mammalian cell or fraction thereof with an agent that can modulate the activity of Tie1; and evaluating the mammalian cell or fraction thereof. In one embodiment, the agent is contacted to the cell while the cell is living, and the evaluating includes isolating a fraction of the cell. In one embodiment, the agent is a protein, e.g., an antibody or a peptide. In one embodiment, the agent includes the HC and LC immunoglobulin variable domains of the E3 antibody or domains that are at least 90% identical in the CDR regions to the E3 antibody. In one embodiment, the agent includes the HC and LC immunoglobulin variable domains of the B2 or D11 antibody or domains that are at least 90% identical in the CDR regions to the B2 or D11 antibody. In one embodiment, the agent includes the HC and LC immunoglobulin variable domains of the A2, A10, P-B1, P-B3, or P-C6 antibody or domains that are at least 70, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100% identical % identical in the CDR regions to the A2, A10, P-B1, P-B3, or P-C6 antibody. In one embodiment, the agent includes the HC and LC immunoglobulin variable domains of the G2 or C7 antibody or domains that are at least 90% identical in the CDR regions to the G2, or C7 antibody. The agent can include other features described herein.

In another aspect, the invention features a method of evaluating a test compound. The method includes evaluating interaction between an agent that can modulate the activity of Tie1 and a protein that includes at least a region of the Tie1 extracellular domain in the presence of the test compound. In one embodiment, the agent is a test compound is a small organic compound with molecular weight less than 8000, 7000, 6000, 5000, or 3000 Daltons. For example, the evaluating includes contacting cells that include the protein that includes at least a region of the Tie1 extracellular domain with the agent in the presence of the test compound. In another example, the evaluating includes forming a cell-free preparation that includes the protein that includes at least a region of the Tie1 extracellular domain, the agent, and the test compound.

In another aspect, the invention features an artificial protein complex that includes (i) a protein that includes a Tie1 extracellular domain and (ii) a ligand that can agonize or antagonize an activity of Tie1. In one embodiment, the ligand is an antibody (e.g., an antibody described herein. For example, the ligand includes the HC and LC immunoglobulin variable domains of an antibody selected from the group consisting of: E3, B2, D11, A2, A10, P-B1, P-B3, P-C6, G2 and C7, or immunoglobulin domains that are at least 90% identical in the CDR regions to the CDR regions of the respective antibody. In one embodiment, the complex is present in a membrane fraction or on a mammalian cell.

In another aspect the invention features a method that includes: administering a composition that includes a protein that interacts with Tie1 (e.g., a protein described herein) to a subject in an amount effective to modulate (e.g., reduce or increase) angiogenesis in the subject.

For example, the protein binds with an affinity K_(D) of less than 10⁻⁸ M, 5·10⁻⁹ M, 10⁻⁹ M, 10⁻¹⁰M, 10⁻¹¹ M, or 10⁻¹² M.

In one embodiment, one or more of the CDRs of the heavy and/or light chain variable domain sequence are human, primate, non-rodent (e.g., non-mouse or non-rat), or synthetic. In one embodiment, one or more of the framework regions of the heavy and/or light chain variable domain sequence are human, primate, or non-rodent (e.g., non-mouse or non-rat).

In one embodiment, the heavy chain includes one or more of the following properties:

i) a HC CDR1 that includes an amino acid sequence as follows:

(AGSR)-Y-(GVK)-M-(GSVF), (SEQ ID NO:117)

(AGSIMRH)-Y-(GVMK)-M-(GSVMFH) (SEQ ID NO:118), or

(AGSIMRNH)-Y-(AGTVMKPQ)-M-(AGSTVMYWFKH) (SEQ ID NO:119);

ii) a HC CDR2 that includes an amino acid sequence as follows:

X-I-Y-P-S-G-G-X-T-X-Y-A-D-S-V-K-G (SEQ ID NO:120), wherein X is any amino acid,

(GSV)-I-(SY)-P-S-G-G-(WQ)-T-(GY) (SEQ ID NO:121),

(GSV)-I-(SY)-P-S-G-G-(WQ)-T-(GY)-Y-A-D-S-V-K-G (SEQ ID NO:122), or

(GSVW)-I-(SY)-P-S-G-G-(AGVMYWPQH)-T-(AGSTLVMYFKH) (SEQ ID NO:123);

iii) a HC CDR3 that includes an amino acid sequence as follows:

V-(four or five residues)-F-D-(I/Y) (SEQ ID NO:124),

G-Y-G-P-I-A-P-G-L-D-Y (SEQ ID NO:125),

(GV)-N-Y-Y-(GYD)-S-(SD)-G-Y-G-P-I-A-P-G-L-D-Y (SEQ ID NO:126),

(GVD)-(AGLN)-(LYR)-(GSTLYH)-(GYD)-(AGSYFP)-(SFD)-(AGYD)-(IY)-(GFD)-(YDP)-(IP)-A-P-G-L-D-Y (SEQ ID NO:127), or

VNYYDSSGYGPIAPGLDY (SEQ ID NO:128).

In one embodiment, the light chain includes one or more of the following properties:

i) a LC CDR1 that includes an amino acid sequence as follows:

R-A-S-Q-S-(IV)-S-(SR)-X1-Y-L-(AN) (SEQ ID NO:129),

R-A-S-Q-S-V-S-S-X-L (SEQ ID NO:130),

R-A-S-Q-S-(IV)-S-(SR)-(SY)-(LY)-(ALN) (SEQ ID NO:131), or

R-A-S-(REQ)-(GSTRN)-(IV)-(GSTIRN)-(STIRH)-X1-(SYWNH)-(LV)-(ASN) (SEQ ID NO:132), wherein X1 can be serine or absent;

ii) a LC CDR2 that includes an amino acid sequence as follows:

X-A-S-X-R-A-T (SEQ ID NO:133), wherein X can be any amino acid,

(AGD)-A-S-(STN)-R-A-T (SEQ ID NO:134),

(AGD)-A-S-(STN)-(LR)-(AEQ)-(ST) (SEQ ID NO:135), or

(AGTKDEH)-A-S-(STN)-(LR)-(AVEQ)-(ST) (SEQ ID NO:136); and

iii) a LC CDR3 that includes an amino acid sequence as follows:

Q-Q-(SYFR)-(GSYN)-S-(STYW)-(RP)-(LWR)-(TIY)-T (SEQ ID NO:137),

(LQ)-Q-(SYFR)-(GSYN)-(SKN)-(STYW)-(RP)-(LWR)-(TIY)-T (SEQ ID NO:138),

Q-Q-(YR)-(GS)-S-(SW)-P-R-X1-T (SEQ ID NO:139), wherein X1 is any amino acid or absent,

(LQ)-(LQ)-(SYFRD)-(GSYN)-(STRKN)-(STYWF)-(RP)-(ILMWRH)-(TIY)-(TI) (SEQ ID NO:140), or

(LQ)-(LRQ)-(SYFRD)-(GSYN)-(ASTRKN)-(STYWF)-(SVRP)-(STILMWRH)-(TIY)-(STI) (SEQ ID NO:141); and

In one embodiment, the light chain includes one or more of the following properties:

i) a LC CDR1 that includes an amino acid sequence as follows:

S-X-(ND)-(IV)-(AG)-X1-X2-X3 (SEQ ID NO:142), or

T-(GR)-(ST)-S-X5-(ND)-(IV)-(AG)-X1-X2-X3-Y-X4-S (SEQ ID NO:143), wherein X1 is any amino acid (e.g., G or R), X2 is any amino acid (e.g., Y or N), X3 is any amino acid (e.g., F, N, or K), X4 is any amino acid (e.g., aliphatic, e.g., V or A);

iii) a LC CDR2 that includes an amino acid sequence as follows:

(DE)-V-N-N-R-P-S (SEQ ID NO:144)

(DE)-(VD)-(STDN)-(YRDN)-R-P-S (SEQ ID NO:145);

v) a LC CDR3 that includes an amino acid sequence as follows:

(SQ)-S-(SY)-(ASID)-(GSR)-(ST)-(STRN)-(STYR)-(ATLY)-(SVWQ) (SEQ ID NO:146)

In one embodiment, the HC CDR2 includes an amino acid sequence as follows: (GSVW)-I-(SY)-P-SG-G-(AGVMYWPQH)-T-(AGSTLVMYFKH)-Y-(AT)-D-S-V-K-G (SEQ ID NO:147) or (GSV)-I-(SY)-P-SG-G-(WQ)-T-(GY)-Y-(AT)-D-S-V-K-G (SEQ ID NO:148).

In one embodiment, the HC CDR1 amino acid sequences have a length of at least 5 amino acids of which at least 3, 4, or 5 amino acids are identical to the CDR1 sequence of the HC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. In one embodiment, the HC CDR2 amino acid sequences have a length of at least 15, 16, or 17 amino acids of which at least 10, 12, 14, 15, 16, or 17 amino acids are identical to the CDR2 sequence of the HC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. In one embodiment, the HC CDR2 amino acid sequences have a length of at least 17 amino acids of which at least 14, 15, 16, or 17 amino acids are identical to the CDR2 sequence of the HC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. In one embodiment, the HC CDR3 amino acid sequences have a length of at least of at least 7 or 8 amino acids of which at least 5, 6, 7, or 8 amino acids are identical to the CDR3 sequence of the HC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

In one embodiment, the LC CDR1 amino acid sequences have a length of at least 10, 11, or 12 amino acids of which at least 7, 8, 9, 10, or 11 amino acids are identical to the CDR1 sequence of the LC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. In one embodiment, the LC CDR2 amino acid sequences have a length of at least 6 or 7 amino acids of which at least 5, 6, or 7 amino acids are identical to the CDR2 sequence of the LC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4. In one embodiment, the LC CDR3 amino acid sequences have a length of at least of at least 8, 9, or 10 amino acids of which at least 7, 8, 9, or 10 amino acids are identical to the CDR3 sequence of the LC of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

In one embodiment, the amino acid sequence of the HC variable domain sequence is at least 70, 80, 85, 90, 92, 95, 97, 98, 99, or 100% identical to the amino acid sequence of the HC variable domain of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

In one embodiment, the amino acid sequence of the LC variable domain sequence is at least 70, 80, 85, 90, 92, 95, 97, 98, 99, or 100% identical to the amino acid sequence of the LC variable domain of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

In one embodiment, the amino acid sequences of the HC and LC variable domain sequences are at least 70, 80, 85, 90, 92, 95, 97, 98, 99, or 100% identical to the amino acid sequences of the HC and LC variable domains of a clone selected from the group consisting of E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, and s-H4.

In one embodiment, the amino acid sequences of one or more framework regions (e.g., FR1, FR2, FR3, and/or FR4) of the HC and/or LC variable domain are at least 70, 80, 85, 90, 92, 95, 97, 98, 99, or 100% identical to corresponding framework regions of the HC and LC variable domains of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

In one embodiment, the light chain variable domain sequence is human or non-immunogenic in a human. In one embodiment, the heavy chain variable domain sequence is human or non-immunogenic in a human.

The protein can bind to cells that express Tie1, e.g., endothelial cells. In one embodiment, the protein does not substantially bind (e.g., does not detectably bind) to platelets.

In one embodiment, the protein specifically binds to Tie1, e.g., it binds with at least a 10, 50, 100, 10³, or 10⁴ fold preference for Tie1 relative to another human protein, e.g., Tie2, a natural protein other than Tie1 that has a Ig-like domain, an EGF-like domain, or fibronectin Type III repeat, or human serum albumin. In one embodiment, the protein binds to a domain of Tie1 described herein.

In one embodiment, the protein is delivered locally. In one embodiment, the protein is delivered systemically.

In one embodiment, the subject is in need of reduced angiogenesis, or identified as such. For example, the subject has an angiogenesis-related disorder. In another example, the subject has a neoplastic disorder, e.g., a metastatic cancer. For example, the subject has an angiogenesis-dependent cancer or tumor.

In another embodiment, the subject has an inflammatory disorder, e.g., rheumatoid arthritis or psoriasis.

In one embodiment, the protein is administered in an amount effective to reduce one or more of the following activities: sprouting, splitting and remodeling of blood vessels. In one embodiment, the protein is administered in an amount effective to reduce vasculogenesis or tubule formation.

In one embodiment, the method further includes, prior to the administering, identifying the subject as a subject in need of reduced angiogenesis. In one embodiment, the method further includes administering the protein continuously or in separate boluses. In one embodiment, the method further includes monitoring the subject during the course of administration. For example, the monitoring includes imaging blood vessels (locally or throughout) the subject. For example, the imaging includes administering the same or different Tie1 binding ligand to the subject.

In another aspect the invention features a method that includes: administering a composition that includes a protein described herein (e.g., a protein that reduces a Tie1 activity) to a subject in an amount effective to reduce a Tie1 activity in the subject. The method can include other features described herein.

In another aspect the invention features a method that includes: administering a composition that includes a protein described herein (e.g., a protein that increase a Tie1 activity) to a subject in an amount effective to increase Tie1 activity in the subject. The method can include other features described herein.

In one embodiment, the composition is administered locally, e.g., to a wound. For example, the subject is in need of treatment for wound healing (e.g., a burn, laceration, or surgery).

In one embodiment, the method includes administering a first antibody that includes one or more CDRs of the E3 antibody and a second antibody that includes one or more CDRs of the G2 or C7 antibody.

In another aspect, the invention features a method that includes administering a composition that includes a protein described herein that modulates an activity of Tie1 to a subject in an amount effective to modulate Tie1 activity in the subject. In one embodiment, the method includes administering first and second proteins that both interact with Tie1. For example, the first protein that agonizes Tie1 activity and second protein that antagonizes Tie1 activity is administered, e.g., to precisely titrate activity. For example, the first and second protein can be administered to different locations to inhibit angiogenesis in one area without affecting another area.

In one embodiment, the first and second proteins are administered separately. In another embodiment, the first and second proteins are administered as a combination. The method can include other features described herein.

In another aspect the invention features a method that includes: administering a composition that includes a protein described herein (e.g., a protein that can modulate an activity of Tie1) to a subject in an amount effective to modulate endothelial cell activity in the subject. In one embodiment, the protein is delivered into the circulation.

In one embodiment, the composition is effective for sensitizing endothelial cells to a treatment, and providing a treatment to the subject that inhibits, kills, ablates, or otherwise arrests the sensitized endothelial cells.

In another aspect the invention features a method that includes: (i) contacting the sample (and optionally, a reference, e.g., control, sample) with a protein that binds to Tie1, e.g., a protein described herein, under conditions that allow interaction of the Tie1-binding ligand and the Tie1 protein to occur; and (ii) detecting formation of a complex between the Tie1-binding ligand, and the sample (and optionally, the reference, e.g., control, sample).

In another aspect the invention features a method that includes: (i) administering to a subject (and optionally a control subject) an Tie1-binding ligand (e.g., an antibody or antigen binding fragment thereof), under conditions that allow interaction of the Tie1-binding ligand and the Tie1 protein to occur; and (ii) detecting formation of a complex between the Tie1-binding ligand and a Tie1 molecule of the subject or detecting distribution of Tie1-binding ligand or at least one location of the Tie1-binding ligand in the subject. In one embodiment, the Tie1-binding ligand does not modulate the activity of Tie1. The Tie1-binding ligand can be a protein described herein. In one embodiment, the ligand detects activated Tie1.

An antibody that binds to Tie1 is preferably mono specific, e.g., a monoclonal antibody, or antigen-binding fragment thereof. For example, the antibody can recognize Tie1 on a living cell, e.g., an endogenous Tie1 molecule or a Tie1 molecule that is expressed from a heterologous nucleic acid. In one embodiment, the Tie1-binding ligand interacts with primary endothelial cells. The term “monospecific antibody” refers to an antibody that displays a single binding specificity and affinity for a particular target, e.g., epitope. This term includes a “monoclonal antibody” which refers to an antibody that is produced as a single molecular species, e.g., from a population of homogenous isolated cells. A “monoclonal antibody composition” refers to a preparation of antibodies or fragments thereof of in a composition that includes a single molecular species of antibody. In one embodiment, a monoclonal antibody is produced by a mammalian cell. One or more monoclonal antibody species may be combined.

The Tie1-binding antibodies can be full-length (e.g., an IgG (e.g., an IgG1, IgG2, IgG3, IgG4), IgM, IgA (e.g., IgA1, IgA2), IgD, and IgE) or can include only an antigen-binding fragment (e.g., a Fab, F(ab′)₂ or scFv fragment), e.g., it does not include an Fc domain or a CH2, CH3, or CH4 sequence. The antibody can include two heavy chain immunoglobulins and two light chain immunoglobulins, or can be a single chain antibody. The antibodies can, optionally, include a constant region chosen from a kappa, lambda, alpha, gamma, delta, epsilon or a mu constant region gene. An Tie1-binding antibody can include a heavy and light chain constant region substantially from a human antibody, e.g., a human IgG1 constant region or a portion thereof. As used herein, “isotype” refers to the antibody class (e.g., IgM or IgG1) that is encoded by heavy chain constant region genes.

In one embodiment, the antibody (or fragment thereof) is a recombinant or modified antibody, e.g., a chimeric, a humanized, a deimmunized, or an in vitro generated antibody. The term “recombinant” or “modified” human antibody, as used herein, is intended to include all antibodies that are prepared, expressed, created or isolated by recombinant means, such as antibodies expressed using a recombinant expression vector transfected into a host cell, antibodies isolated from a recombinant, combinatorial antibody library, antibodies isolated from an animal (e.g., a mouse) that is transgenic for human immunoglobulin genes or antibodies prepared, expressed, created or isolated by any other means that involves splicing of human immunoglobulin gene sequences to other DNA sequences. Such recombinant antibodies include humanized, CDR grafted, chimeric, deimmunized, in vitro generated antibodies, and may optionally include constant regions derived from human germline immunoglobulin sequences.

In one embodiment, the antibody binds to an epitope distinct from an epitope bound by known monoclonal antibodies that bind to Tie1, e.g., an antibody described in WO 95/26364, e.g., 3C4C7G6 and 10F11G6. In other embodiments, the antibody does not compete with known monoclonal antibodies that bind to Tie1, e.g., 3C4C7G6 and 10F11G6. In still other embodiments, the antibody does not compete with ligand described herein.

Also within the scope of the invention are antibodies or other ligands that bind overlapping epitopes of, or competitively inhibit the binding of the ligands disclosed herein to Tie1. For example, the antibodies or other ligands bind overlapping epitopes of or competitively inhibit the binding of monospecific antibodies, e.g., E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4 to Tie1, or vice versa (e.g., the monospecific antibodies competitively inhibiting binding of the ligands). Overlapping epitopes can include at least one amino acid in common. Ligands that competitively inhibit binding of one another do not necessarily bind to overlapping epitopes. For example, they may inhibit binding by steric interference or by altering the conformation of Tie1.

Any combination of Tie1-binding ligands is within the scope of the invention, e.g., two or more antibodies that bind to different regions of Tie1, e.g., antibodies that bind to two different epitopes on the extracellular domain of Tie1, e.g., a bispecific antibody.

In one embodiment, the Tie1-binding antibody or antigen-binding fragment thereof includes at least one light or heavy chain immunoglobulin (or preferably, at least one light chain immunoglobulin and at least one heavy chain immunoglobulin). Preferably, each immunoglobulin includes a light or a heavy chain variable region having at least one, two and, preferably, three complementarity determining regions (CDR's) substantially identical to a CDR from an anti-Tie1 light or heavy chain variable region, respectively, i.e., from a variable region of an antibody described herein, e.g., E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.

An Tie I-binding ligand described herein can be used alone, e.g., can be administered to a subject or used in vitro in non-derivatized or unconjugated forms. In other embodiments, the Tie I-binding ligand can be derivatized, modified or linked to another functional molecule, e.g., another polypeptide, protein, isotope, cell, or insoluble support. For example, the Tie1-binding ligand can be functionally linked (e.g., by chemical coupling, genetic fusion, non-covalent association or otherwise) to one or more other molecular entities, such as an antibody (e.g., if the ligand is an antibody to form a bispecific or a multi-specific antibody), a toxin, a radioisotope, a therapeutic (e.g., a cytotoxic or cytostatic) agent or moiety, among others. For example, the Tie1-binding ligand can be coupled to a radioactive ion (e.g., an α-, γ-, or β-emitter), e.g., iodine (¹³¹I or ¹²⁵I), yttrium (⁹⁰Y), lutetium (¹⁷⁷Lu), actinium (²²⁵Ac), rhenium (¹⁸⁶ Re), or bismuth (²¹²Bi or ²¹³Bi).

In another aspect, the invention features a nucleic acid that includes a coding sequence that encodes a polypeptide comprising an immunoglobulin heavy or light chain variable domain that binds to Tie1, e.g., an immunoglobulin heavy or light chain variable domain described herein. For example, the nucleic acid can include a particular nucleic acid sequence described herein, a nucleic acid that is at least 75, 80, 85, 90, 95, 96, 97, 98, or 99% identical to a nucleic acid sequence described herein (e.g., a particular nucleic acid sequence), or a nucleic acid that specifically hybridizes (e.g., under conditions described herein) to a nucleic acid sequence described herein (e.g., a particular nucleic acid sequence), or fragments thereof (e.g., CDR-coding fragments).

A nucleic acid described herein can further include a promoter operably linked to the coding sequence. A nucleic acid can include a first and second coding sequence, e.g., wherein the first coding sequence encodes a polypeptide that includes an immunoglobulin heavy chain variable domain and the second coding sequence encodes a polypeptide that includes an immunoglobulin light chain variable domain.

In another aspect, the invention features a host cell that contains a first nucleic acid encoding a polypeptide comprising a heavy chain variable region and a second nucleic acid encoding a polypeptide comprising a light chain variable region. The heavy chain variable region and the light chain variable region can associate to form a Tie1 binding protein. These variable regions can have one or more properties described herein, e.g., at least 75, 80, 85, 90, 95, 96, 97, 98, or 99% identity to a sequence described herein. The invention also includes a method of providing a Tie1-binding antibody. The method can include providing a host cell described herein; and expressing said first and second nucleic acids in the host cell under conditions that allow assembly of said light and heavy chain variable regions to form an antigen binding protein that interacts with Tie1.

In another aspect, the invention provides compositions, e.g., pharmaceutical compositions, which include a pharmaceutically acceptable carrier, excipient or stabilizer, and at least one of the Tie1-binding ligands (e.g., antibodies or fragments thereof) described herein. In one embodiment, the compositions, e.g., the pharmaceutical compositions, include a combination of two or more of the aforesaid Tie1-binding ligands.

In another aspect, the invention features a kit that includes an Tie1-binding antibody (or fragment thereof), e.g., an Tie1-binding antibody (or fragment thereof) as described herein, for use alone or in combination with other therapeutic modalities, e.g., a cytotoxic or labeling agent, e.g., a cytotoxic or labeling agent as described herein, along with instructions on how to use the Tie1 antibody or the combination of such agents to treat, prevent or detect a Tie1-related disorder, e.g., an endothelial cell related disorder, e.g., rheumatoid arthritis or metastatic cancer.

In another aspect, the protein ligand that binds to Tie1 is a polypeptide that is not an immunoglobulin. For example, the polypeptide can be of variable length, e.g., 4 to 100 amino acid residues in length, preferably 5 to 75, 6 to 50, or 7 to 40 amino acid residues in length, or more preferably 8 to 30 or 10 to 25 amino acid residues in length. In some embodiments, the polypeptide includes non-standard or synthetic amino acid residues, e.g., norleucine, selenocysteine, pyrrolysine, etc. In some embodiments, the polypeptide includes cross-linking groups, e.g., two cysteine residues that can form a disulfide bond or some other type of chemical cross-linking moieties that can be used to cyclize the peptide. In other preferred embodiments, the polypeptide can be modified, e.g., using polyethylene glycol or fusion to a soluble protein, e.g., to increase the solubility or circulatory half-life of the polypeptide.

In another aspect, the invention features a method of identifying a protein that specifically binds to Tie1. In preferred embodiments, the invention includes: providing a Tie1 antigen; providing a display library (e.g., a phage display library member); identifying a member present in the library, wherein the member expresses a protein that specifically binds to the Tie1 antigen. The term “Tie1 antigen” refers to any antigenic fragment of Tie1 that is at least 8 amino acids in length. For example, a Tie1 antigen can include a fragment of the Tie1 ectodomain, e.g., a fragment that includes a folded protein domain such as a fragment described herein. In some embodiments, the Tie1 antigen is of human origin and includes, e.g., the extracellular domain of human Tie1 or a fragment thereof (e.g., a fragment described herein. The Tie1 antigen can be a recombinant polypeptide optionally fused to another polypeptide, e.g., a Fc domain, or it can be a cell that expresses Tie1 on its surface (e.g., an endothelial cell). In other preferred embodiments, the Tie1 antigen has an activated conformation, e.g., the Tie1 antigen is a dimeric conformation or a conformation stabilized by the E3 antibody described herein.

The methods described here are, for example, applicable to libraries that are based on bacteriophage with a substantially complete genome (e.g., including a modified gene III) and to libraries that are based on bacteriophage particles that include a phagemid nucleic acid. The terms “bacteriophage library member” and “phage” encompass members of both types of libraries. The term “bacteriophage particle” refers to a particle formed of bacteriophage coat proteins that packages a nucleic acid. The packaged nucleic acid can be a modified bacteriophage genome or a phagemid, e.g., a nucleic acid that includes a bacteriophage origin of replication but lacks essential phage genes and cannot propagate in E. coli without help from “helper phage” or phage genes supplied in trans.

In other embodiments, the invention features a method of identifying a protein that specifically binds to Tie1. The method includes: providing a Tie1 antigen (e.g., an region of the Tie1 ectodomain); immunizing a non-human animal with the Tie1 antigen; and isolating a cell that produces a immunoglobulin that interacts with Tie1. For example, the method can include producing hybridoma cells from the spleen of the animal (e.g., an immunized mouse); and identifying individual hybridoma cell lines expressing an antibody that specifically binds to the Tie1 antigen. For example, the

In preferred embodiments, the Tie1 antigen is of human origin and includes, e.g., the extracellular domain of human Tie1 or some fragment thereof, e.g., the HA binding domain of Tie1. The Tie1 antigen can be a recombinant polypeptide optionally fused to another polypeptide, e.g., a purification handle, or it can be a cell that expresses Tie1 (e.g., an endothelial cell) on its surface. In other preferred embodiments, the Tie1 antigen has an activated conformation, e.g., dimerized.

In preferred embodiments, the methods further include isolating a nucleic acid molecule from the identified phage or hybridoma, wherein the nucleic acid molecule encodes the polypeptide or antibody that specifically binds to the Tie1 antigen. The isolated nucleic acid molecules can be used to produce therapeutic agents, as described herein.

In another aspect, the invention features nucleic acids that encode proteins identified by the methods described herein. In preferred embodiments, the nucleic acids include sequences encoding a heavy and light chain immunoglobulin or immunoglobulin fragment described herein. For example, the invention features, a first and second nucleic acid encoding a heavy and light chain variable region, respectively, of an Tie1-binding antibody molecule as described herein. Sequences encoding a heavy and light chain that function together can be present on separate nucleic acid molecules or on the same nucleic acid molecule. In another aspect, the invention features host cells and vectors containing a nucleic acid described herein.

In yet another aspect, the invention features a method of producing an Tie1-binding antibody, or antigen-binding fragment thereof. The method includes: providing a host cell that contains a first nucleic acid encoding a polypeptide comprising a heavy chain variable region, e.g., a heavy chain variable region as described herein; providing a second nucleic acid encoding a polypeptide comprising a light chain variable region, e.g., a light chain variable region as described herein; and expressing said first and second nucleic acids in the host cell under conditions that allow assembly of said light and heavy chain variable regions to form an antigen binding protein that interacts with Tie1. The first and second nucleic acids can be linked or unlinked, e.g., expressed on the same or different vector, respectively. The first and second nucleic acids can be components of the same molecule or can reside on different molecules (e.g., different chromosomes or plasmids).

The host cell can be a eukaryotic cell, e.g., a mammalian cell, an insect cell, a yeast cell, or a prokaryotic cell, e.g., E. coli. For example, the mammalian cell can be a cultured cell or a cell line. Exemplary mammalian cells include lymphocytic cell lines (e.g., NSO), Chinese hamster ovary cells (CHO), COS cells, oocyte cells, and cells from a transgenic animal, e.g., mammary epithelial cell. For example, nucleic acids encoding the antibodies described herein can be expressed in a transgenic animal. In one embodiment, the nucleic acids are placed under the control of a tissue-specific promoter (e.g., a mammary specific promoter) and the antibody is produced in the transgenic animal. For example, the antibody molecule is secreted into the milk of the transgenic animal, such as a transgenic cow, pig, horse, sheep, goat or rodent. To produce a single chain antibody, the nucleic acid is configured to encode a single polypeptide that comprises both the heavy and light chain variable domains.

Tie1 has been found to be overexpressed in association with a wide range of cancers. Targeting Tie1 on the tumor vasculature with Tie1-binding ligands (e.g., antibodies) can be used to inhibit, destroy, or otherwise antagonize the vasculature so that tumor growth and metastasis is reduced. The ligands can be, for example, associated with a toxic payload or can mediate direct functional inhibition.

In another aspect, the invention features a method of inhibiting an activity of a cell, e.g., an endothelial cell, e.g., proliferation, adhesion, growth or survival of a cell, e.g., an endothelial cell, e.g., an endothelial cell in the vicinity of a cancer, e.g., a tumor. Methods of the invention include contacting the cell with a Tie1-binding ligand, in an amount sufficient to inhibit the adhesion, migration, growth or proliferation of the cell. Methods of the invention can be used, for example, to treat or prevent a disorder, e.g., an inflammatory disorder (e.g., rheumatoid arthritis, lupus, restenosis, psoriasis, graft v. host response, or multiple sclerosis), or a cancerous disorder (e.g., a malignant or metastatic disorder), by administering to a subject (e.g., an experimental animal or a human patient) a Tie1-binding ligand in an amount effective to treat or prevent such disorder. a Tie1-binding ligand can also be used to treat or prevent stroke, heart disease, ulcers, scleroderma, infertility, and other diseases that are associated with insufficient angiogenesis.

A Tie1-binding ligand can be used to treat or prevent angiogenesis-related disorders, particularly angiogenesis-dependent cancers and tumors.

Angiogenesis-related disorders include, but are not limited to, solid tumors; blood born tumors such as leukemias; tumor metastasis; benign tumors (e.g., hemangiomas, acoustic neuromas, neurofibromas, trachomas, and pyogenic granulomas; rheumatoid arthritis); psoriasis; ocular angiogenic diseases, for example, diabetic retinopathy, retinopathy of prematurity, macular degeneration, corneal graft rejection, neovascular glaucoma, retrolental fibroplasia, rubeosis; Osler-Webber Syndrome; myocardial angiogenesis; plaque neovascularization; telangiectasia; hemophiliac joints; angiofibroma; and wound granulation.

“Angiogenesis-dependent cancers and tumors” are cancers tumors that require, for their growth (expansion in volume and/or mass), an increase in the number and density of the blood vessels supplying then with blood. In one embodiment a Tie1-binding ligand causes regression of such cancers and tumors. “Regression” refers to the reduction of tumor mass and size, e.g., a reduction of at least 2, 5, 10, or 25%.

In another aspect, the invention features a method of contacting a cell (in vitro, ex vivo, or in vivo), e.g., an endothelial cell, e.g., an endothelial cell in the vicinity of a cancer, e.g., a tumor. The method can include providing a ligand that interacts with Tie1, e.g., a ligand described herein, and contacting the cell with the ligand, in an amount sufficient to form at least one detectable ligand-cell complex. The ligand can include, for example, a label or cytotoxic entity, e.g., an immunoglobulin Fc domain or a cytotoxic drug.

In another aspect, the invention features a method of treating, e.g., inhibiting, ablating or killing, a cell or impairing at least one activity of the cell. The method includes providing an Tie1-binding ligand, e.g. a ligand described herein, and contacting the cell with the ligand, in an amount sufficient to impair at least one activity of the cell, inhibit, ablate or kill the cell. The contacting can be in vitro or in vivo. For example, the cell can be e.g., an endothelial cell, e.g., an endothelial cell in the vicinity of a cancer, e.g., a tumor. The ligand can include a cytotoxic entity. Methods of the invention can be used, for example, to treat or prevent a disorder, e.g., a endothelial cell-based disorder, a blood vessel disorder, wound healing, or a cancerous disorder (e.g., a malignant or metastatic disorder), by administering to a subject (e.g., an experimental animal or a human patient) an Tie1-binding ligand in an amount effective to treat or prevent such disorder.

The subject methods can be used on cells in culture, e.g. in vitro or ex vivo. For example, an endothelial cell, e.g., an endothelial cell in cancer biopsy, can be cultured in vitro in culture medium and the contacting step can be effected by adding the Tie1-binding ligand to the culture medium. The method can be performed on cells (e.g., cancerous or metastatic cells) present in a subject, as part of an in vivo (e.g., therapeutic or prophylactic) protocol. For in vivo embodiments, the contacting step is effected in a subject and includes administering the Tie1-binding ligand to the subject under conditions effective to permit both binding of the ligand to the cell, and the inhibition of adhesion, migration, growth or proliferation of the cell.

The method of the invention can be used to treat or prevent cancerous disorders, e.g., including but are not limited to, solid tumors, soft tissue tumors, and metastatic lesions, particularly tumors that require a blood supply or angiogenesis. Examples of solid tumors include malignancies, e.g., sarcomas, adenocarcinomas, and carcinomas, of the various organ systems, such as those affecting lung, breast, lymphoid, gastrointestinal (e.g., colon), and genitourinary tract (e.g., renal, urothelial cells), pharynx, as well as adenocarcinomas which include malignancies such as most colon cancers, rectal cancer, renal-cell carcinoma, liver cancer, non-small cell carcinoma of the lung, cancer of the small intestine and cancer of the esophagus. The subject can be a mammal, e.g., a primate, preferably a higher primate, e.g., a human (e.g., a patient having, or at risk of, a disorder described herein, e.g., an endothelial cell-based disorder, e.g., cancer).

The Tie1-binding antibody or fragment thereof, e.g., an Tie1-binding antibody or fragment thereof as described herein, can be administered to the subject systemically (e.g., orally, parenterally, subcutaneously, intravenously, intramuscularly, intraperitoneally, intranasally, transdermally, or by inhalation), topically, or by application to mucous membranes, such as the nose, throat and bronchial tubes.

The methods can further include the step of monitoring the subject, e.g., for a reduction in one or more of: a reduction in tumor size; reduction in cancer markers, e.g., levels of cancer specific antigen; reduction in the appearance of new lesions, e.g., in a bone scan; a reduction in the appearance of new disease-related symptoms; or decreased or stabilization of size of soft tissue mass; or any parameter related to improvement in clinical outcome. The subject can be monitored in one or more of the following periods: prior to beginning of treatment; during the treatment; or after one or more elements of the treatment have been administered. Monitoring can be used to evaluate the need for further treatment with the same Tie1-binding ligand or for additional treatment with additional agents. Generally, a decrease in one or more of the parameters described above is indicative of the improved condition of the subject. Information about the monitoring can be recorded, e.g., in electronic or digital form.

The Tie1-binding ligand can be used alone in unconjugated form to thereby inhibit adhesion, migration, or extravasation or the Tie1-expressing cells, or ablate or kill the Tie1-expressing cells. If the ligand is an antibody, the ablation or killing can be mediated, e.g., by an antibody-dependent cell killing mechanisms such as complement-mediated cell lysis and/or effector cell-mediated cell killing. In other embodiments, the Tie1-binding ligand can be bound (e.g., physically associated, either directly or indirectly, covalently or non-covalently) to a substance, e.g., a cytotoxic agent or moiety, effective to kill or ablate the Tie1-expressing cells. For example, the Tie1-binding ligand can be coupled to a radioactive ion (e.g., an α-, γ-, or β-emitter), e.g., iodine (¹³¹I or ¹²⁵I), yttrium (⁹⁰Y), lutetium (¹⁷⁷ Lu), actinium (²²⁵Ac), or bismuth (²¹³Bi). The methods and compositions of the invention can be used in combination with other therapeutic modalities. In one embodiment, the methods of the invention include administering to the subject an Tie1-binding ligand, e.g., an Tie1-binding antibody or fragment thereof, in combination with a cytotoxic agent, in an amount effective to treat or prevent said disorder. The ligand and the cytotoxic agent can be administered simultaneously or sequentially. In other embodiments, the methods and compositions of the invention are used in combination with surgical and/or radiation procedures.

In another aspect, the invention features methods for detecting the presence of a Tie1 protein or a cell expressing Tie1 (e.g., an endothelial cell) in a sample, in vitro (e.g., a biological sample, a tissue biopsy, e.g., a cancerous lesion). The subject method can be used to evaluate, e.g., diagnose or stage a disorder described herein, e.g., a cancerous disorder. The method includes: (i) contacting the sample (and optionally, a reference, e.g., control sample) with an Tie1-binding ligand, as described herein, under conditions that allow interaction of the Tie1-binding ligand and the Tie1 protein to occur; and (ii) detecting formation of a complex between the Tie1-binding ligand, and the sample (and optionally, the reference, e.g., control, sample). Formation of the complex is indicative of the presence of Tie1 protein (e.g., activated Tie1 protein), and can indicate the suitability or need for a treatment described herein. For example, a statistically significant change in the formation of the complex in the sample relative to the reference sample, e.g., the control sample, is indicative of the presence of Tie1 (e.g., activated Tie1) in the sample.

In yet another aspect, the invention provides a method for detecting the presence of Tie1 (e.g., activated Tie1) in vivo (e.g., in vivo imaging in a subject). The subject method can be used to evaluate, e.g., diagnose, localize, or stage a disorder described herein, e.g., a cancerous disorder. The method includes: (i) administering to a subject (and optionally a control subject) an Tie1-binding ligand (e.g., an antibody or antigen binding fragment thereof), under conditions that allow interaction of the Tie1-binding ligand and the Tie1 protein to occur; and (ii) detecting formation of a complex between the ligand and Tie1, wherein a statistically significant change in the formation of the complex in the subject relative to the reference, e.g., the control subject or subject's baseline, is indicative of the presence of the Tie1. The presence of activated Tie1 in particular locations within a subject can be indicative of an endothelial-cell related disorder, e.g., an angiogenesis-related disorder, e.g., a cancer, e.g., metastatic cancer, or other angiogenesis-related disorder described herein.

In other embodiments, a method of diagnosing or staging, a disorder as described herein (e.g., an inflammatory or cancerous disorder), is provided. The method includes: (i) identifying a subject having, or at risk of having, the disorder; (ii) obtaining a sample of a tissue or cell affected with the disorder; (iii) contacting said sample or a control sample with an Tie1-binding ligand, under conditions that allow interaction of the binding agent and the Tie1 protein to occur, and (iv) detecting formation of a complex. A statistically significant increase in the formation of the complex between the ligand with respect to a reference sample, e.g., a control sample, is indicative of the disorder or the stage of the disorder. For example, the finding of activated Tie1 on tumor cells located in a solid tumor can indicate that the tumor is progressing into a metastatic tumor.

Preferably, the Tie1-binding ligand used in the in vivo and in vitro diagnostic methods is directly or indirectly labeled with a detectable substance to facilitate detection of the bound or unbound binding agent. Suitable detectable substances include various enzymes, prosthetic groups, fluorescent materials, luminescent materials and radioactive materials. In one embodiment, the Tie1-binding ligand is coupled to a radioactive ion, e.g., indium (¹¹¹In), iodine (¹³¹I or ¹²¹I), yttrium (⁹⁰Y), actinium (²²⁵Ac), bismuth (²¹³Bi), sulfur (³⁵S), carbon (¹⁴C), tritium (³H), rhodium (¹⁸⁸Rh), or phosphorous (³²P). In another embodiment, the ligand is labeled with an NMR contrast agent.

The invention also provides polypeptides and nucleic acids that encompass a range of amino acid and nucleic acid sequences, e.g., sequences described herein or sequences related to those described herein. For example, the invention features nucleic acids that encodes each of the polypeptides described herein. The nucleic acid can include the cognate codons or any set of codons that can be translated to produce the respective polypeptide. Such polypeptides include individual subunits of a multi-chain protein, e.g., an antibody that includes a plurality of different polypeptide chains. The nucleic acid may also be a nucleic acid fragment or vector that is not expressed, but includes a sequence encoding at least a part of an immunoglobulin variable region (e.g., including a CDR described herein) or a complement thereof. Such nucleic acids can be used to prepare useful constructs, cells, and proteins. In addition, the invention features a host cell that includes a nucleic acid described herein. The cell can express a protein described herein, e.g., on its surface.

As used herein, the term “antibody” refers to a protein that includes at least one immunoglobulin variable domain or immunoglobulin variable domain sequence. For example, an antibody can include a heavy (H) chain variable region (abbreviated herein as VH), and a light (L) chain variable region (abbreviated herein as VL). In another example, an antibody includes two heavy (H) chain variable regions and two light (L) chain variable regions. The term “antibody” encompasses antigen-binding fragments of antibodies (e.g., single chain antibodies, Fab fragments, F(ab′)₂, a Fd fragment, a Fv fragments, and dAb fragments) as well as complete antibodies.

The VH and VL regions can be further subdivided into regions of hypervariability, termed “complementarity determining regions” (“CDR”), interspersed with regions that are more conserved, termed “framework regions” (FR). The extent of the framework region and CDR's has been precisely defined (see, Kabat, E. A., et al. (1991) Sequences of Proteins of Immunological Interest, Fifth Edition, U.S. Department of Health and Human Services, NIH Publication No. 91-3242, and Chothia, C. et al. (1987) J. Mol. Biol. 196:901-917). Kabat definitions are used herein. Each VH and VL is typically composed of three CDR's and four FR's, arranged from amino-terminus to carboxy-terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4.

An “immunoglobulin domain” refers to a domain from the variable or constant domain of immunoglobulin molecules. Immunoglobulin domains typically contain two β-sheets formed of about seven β-strands, and a conserved disulphide bond (see, e.g., A. F. Williams and A. N. Barclay 1988 Ann. Rev Immunol. 6:381-405). The canonical structures of hypervariable loops of an immunoglobulin variable can be inferred from its sequence, as described in Chothia et al. (1992) J. Mol. Biol. 227:799-817; Tomlinson et al. (1992) J. Mol. Biol. 227:776-798); and Tomlinson et al. (1995) EMBO J. 14 (18):4628-38.

As used herein, an “immunoglobulin variable domain sequence” refers to an amino acid sequence which can form the structure of an immunoglobulin variable domain. For example, the sequence may include all or part of the amino acid sequence of a naturally-occurring variable domain. For example, the sequence may omit one, two or more N- or C-terminal amino acids, internal amino acids, may include one or more insertions or additional terminal amino acids, or may include other alterations. In one embodiment, a polypeptide that includes immunoglobulin variable domain sequence can associate with another immunoglobulin variable domain sequence to form a target binding structure (or “antigen binding site”), e.g., a structure that interacts with Tie1, e.g., binds to or inhibits Tie1.

The VH or VL chain of the antibody can further include all or part of a heavy or light chain constant region, to thereby form a heavy or light immunoglobulin chain, respectively. In one embodiment, the antibody is a tetramer of two heavy immunoglobulin chains and two light immunoglobulin chains, wherein the heavy and light immunoglobulin chains are inter-connected by, e.g., disulfide bonds. The heavy chain constant region includes three domains, CH1, CH2 and CH3. The light chain constant region includes a CL domain. The variable region of the heavy and light chains contains a binding domain that interacts with an antigen. The constant regions of the antibodies typically mediate the binding of the antibody to host tissues or factors, including various cells of the immune system (e.g., effector cells) and the first component (Clq) of the classical complement system. The term “antibody” includes intact immunoglobulins of types IgA, IgG, IgE, IgD, IgM (as well as subtypes thereof). The light chains of the immunoglobulin may be of types kappa or lambda. In one embodiment, the antibody is glycosylated. An antibody can be functional for antibody-dependent cytotoxicity and/or complement-mediated cytotoxicity.

One or more regions of an antibody can be human or effectively human. For example, one or more of the variable regions can be human or effectively human. For example, one or more of the CDRs can be human, e.g., HC CDR1, HC CDR2, HC CDR3, LC CDR1, LC CDR2, and LC CDR3. Each of the light chain CDRs can be human. HC CDR3 can be human. One or more of the framework regions can be human, e.g., FR1, FR2, FR3, and FR4 of the HC or LC. In one embodiment, all the framework regions are human, e.g., derived from a human somatic cell, e.g., a hematopoietic cell that produces immunoglobulins or a non-hematopoietic cell. In one embodiment, the human sequences are germline sequences, e.g., encoded by a germline nucleic acid. One or more of the constant regions can be human or effectively human. In another embodiment, at least 70, 75, 80, 85, 90, 92, 95, or 98% of the framework regions (e.g., FR1, FR2, and FR3, collectively, or FR1, FR2, FR3, and FR4, collectively) or the entire antibody can be human or effectively human. For example, FR1, FR2, and FR3 collectively can be at least 70, 75, 80, 85, 90, 92, 95, 98, or 99% identical to a human sequence encoded by a human germline V segment of a locus encoding a light or heavy chain sequence.

All or part of an antibody can be encoded by an immunoglobulin gene or a segment thereof. Exemplary human immunoglobulin genes include the kappa, lambda, alpha (IgA1 and IgA2), gamma (IgG1, IgG2, IgG3, IgG4), delta, epsilon and mu constant region genes, as well as the myriad immunoglobulin variable region genes. Full-length immunoglobulin “light chains” (about 25 Kd or 214 amino acids) are encoded by a variable region gene at the NH2-terminus (about 110 amino acids) and a kappa or lambda constant region gene at the COOH-terminus. Full-length immunoglobulin “heavy chains” (about 50 Kd or 446 amino acids), are similarly encoded by a variable region gene (about 116 amino acids) and one of the other aforementioned constant region genes, e.g., gamma (encoding about 330 amino acids).

The term “antigen-binding fragment” of a full length antibody (or simply “antibody portion,” or “fragment”), as used herein, refers to one or more fragments of a full-length antibody that retain the ability to specifically bind to a target of interest. Examples of binding fragments encompassed within the term “antigen-binding fragment” of a full length antibody include (i) a Fab fragment, a monovalent fragment consisting of the VL, VH, CL and CH1 domains; (ii) a F(ab′)₂ fragment, a bivalent fragment including two Fab fragments linked by a disulfide bridge at the hinge region; (iii) a Fd fragment consisting of the VH and CH1 domains; (iv) a Fv fragment consisting of the VL and VH domains of a single arm of an antibody, (v) a dAb fragment (Ward et al., (1989) Nature 341:544-546), which consists of a VH domain; and (vi) an isolated complementarity determining region (CDR) that retains functionality. Furthermore, although the two domains of the Fv fragment, VL and VH, are coded for by separate genes, they can be joined, using recombinant methods, by a synthetic linker that enables them to be made as a single protein chain in which the VL and VH regions pair to form monovalent molecules known as single chain Fv (scFv). See e.g., Bird et al. (1988) Science 242:423-426; and Huston et al. (1988) Proc. Natl. Acad. Sci. USA 85:5879-5883.

Antibody fragments can be obtained using any appropriate technique including conventional techniques known to those with skill in the art. The term “monospecific antibody” refers to an antibody that displays a single binding specificity and affinity for a particular target, e.g., epitope. This term includes a “monoclonal antibody” or “monoclonal antibody composition,” which as used herein refer to a preparation of antibodies or fragments thereof of single molecular composition. As used herein, “isotype” refers to the antibody class (e.g., IgM or IgG1) that is encoded by heavy chain constant region genes.

In one embodiment, the HC or LC of an antibody includes sequences that correspond to an amino acid sequence encoded by a human germline sequence, e.g., the framework regions and/or in the CDRs. For example, the antibody can include sequences from the human DP47 antibody. In one embodiment, one or more codons for the antibody are altered relative to the germline nucleic acid sequence, but are chosen to encode the same amino acid sequence. Codons can be selected, e.g., to optimize expression in a particular system, create restriction enzyme sites, create a silent fingerprint, etc.

In one embodiment, CDR2 of the antibody HC includes at least 11, 12, 13, 14, or 15 amino acid positions that are identical to the amino acids found in CDR2 of DP47.

A “humanized” immunoglobulin variable region is an immunoglobulin variable region that includes sufficient number of human framework amino acid positions such that the immunoglobulin variable region does not elicit an immunogenic response in a normal human. Descriptions of “humanized” immunoglobulins include, for example, U.S. Pat. No. 6,407,213 and U.S. Pat. No. 5,693,762.

An “effectively human” immunoglobulin variable region is an immunoglobulin variable region that includes a sufficient number of human framework amino acid positions such that the immunoglobulin variable region does not elicit an immunogenic response in a normal human. An “effectively human” antibody is an antibody that includes a sufficient number of human amino acid positions such that the antibody does not elicit an immunogenic response in a normal human.

The term “Tie1 ectodomain” refers to any extracellular region of a Tie1 protein, e.g., a region that includes about amino acids 25-759 of SEQ ID NO:2. Other exemplary regions are regions that include one or more EGF domains (e.g., 214-256, 258-303, 303-345, 214-303, 258-345, or 214-345 of SEQ ID NO:2); one or more IG-Like C2 domains (e.g., 43-105, 43-426, 372-426); one or more Fibronectin Type III repeats (e.g., 446-540, 543-639, 643-744, 446-639, 543-744, or 446-744 of SEQ ID NO:2); and combinations thereof.

As used herein, “binding affinity” refers to the apparent association constant or K_(a). The K_(a) is the reciprocal of the dissociation constant (K_(d)). A ligand may, for example, have a binding affinity of at least 10⁵, 10⁶, 10⁷ or 10⁸ M⁻¹ for a particular target molecule. Higher affinity binding of a ligand to a first target relative to a second target can be indicated by a higher K_(a) (or a smaller numerical value K_(d)) for binding the first target than the K_(a) (or numerical value K_(d)) for binding the second target. In such cases the ligand has specificity for the first target relative to the second target. Differences in binding affinity (e.g., for specificity or other comparisons) can be at least 1.5, 2, 5, 10, 50, 100, or 1000-fold. For example, a Tie1 binding ligand may preferentially bind to Tie at least 1.5, 2, 5, 10, 50, 100, or 1000-fold better than to another antigen, e.g., Tie2, EGF, fibronectin, or human serum albumin. A Tie1 binding ligand may also be species-specific or species-general (e.g., can bind to a Tie1 protein from more than one species).

Binding affinity can be determined by a variety of methods including equilibrium dialysis, equilibrium binding, gel filtration, ELISA, surface plasmon resonance, or spectroscopy (e.g., using a fluorescence assay). These techniques can be used to measure the concentration of bound and free ligand as a function of ligand (or target) concentration. The concentration of bound ligand ([Bound]) is related to the concentration of free ligand ([Free]) and the concentration of binding sites for the ligand on the target where (N) is the number of binding sites per target molecule by the following equation:

[Bound]=N·[Free]/((1/Ka)+[Free])

Although quantitative measurements of Ka are routine, it is not always necessary to make an exact determination of K_(a), though, since sometimes it is sufficient to obtain a qualitative measurement of affinity, e.g., determined using a method such as ELISA or FACS analysis, is proportional to K_(a), and thus can be used for comparisons, such as determining whether a higher affinity is, e.g., 2, 5, 10, 20, or 50 fold higher than a reference. Binding affinity is typically evaluated in 0.01 M HEPES pH 7.4, 0.15 M NaCl, 3 mM EDTA and 0.005% (v/v) surfactant P20.

An “isolated composition” refers to a composition that is removed from at least 90% of at least one component of a natural sample from which the isolated composition can be obtained. Compositions produced artificially or naturally can be “compositions of at least” a certain degree of purity if the species or population of species of interests is at least 5, 10, 25, 50, 75, 80, 90, 95, 98, or 99% pure on a weight-weight basis.

An “epitope” refers to the site on a target compound that is bound by a ligand, e.g., a polypeptide ligand or an antigen-binding ligand (e.g., a Fab or antibody). In the case where the target compound is a protein, for example, an epitope may refer to the amino acids that are bound by the ligand. Overlapping epitopes include at least one common amino acid residue.

As used herein, the term “substantially identical” (or “substantially homologous”) is used herein to refer to a first amino acid or nucleotide sequence that contains a sufficient number of identical or equivalent (e.g., with a similar side chain, e.g., conserved amino acid substitutions) amino acid residues or nucleotides to a second amino acid or nucleotide sequence such that the first and second amino acid or nucleotide sequences have similar activities. In the case of antibodies, the second antibody has the same specificity and has at least 50% of the affinity of the same.

Sequences similar or homologous (e.g., at least about 85% sequence identity) to the sequences disclosed herein are also part of this application. In some embodiment, the sequence identity can be about 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or higher. Alternatively, substantial identity exists when the nucleic acid segments will hybridize under selective hybridization conditions (e.g., highly stringent hybridization conditions), to the complement of the strand. The nucleic acids may be present in whole cells, in a cell lysate, or in a partially purified or substantially pure form.

Calculations of “homology” or “sequence identity” between two sequences (the terms are used interchangeably herein) are performed as follows. The sequences are aligned for optimal comparison purposes (e.g., gaps can be introduced in one or both of a first and a second amino acid or nucleic acid sequence for optimal alignment and non-homologous sequences can be disregarded for comparison purposes). In a preferred embodiment, the length of a reference sequence aligned for comparison purposes is at least 30%, preferably at least 40%, more preferably at least 50%, even more preferably at least 60%, and even more preferably at least 70%, 80%, 90%, 100% of the length of the reference sequence. The amino acid residues or nucleotides at corresponding amino acid positions or nucleotide positions are then compared. When a position in the first sequence is occupied by the same amino acid residue or nucleotide as the corresponding position in the second sequence, then the molecules are identical at that position (as used herein amino acid or nucleic acid “identity” is equivalent to amino acid or nucleic acid “homology”). The percent identity between the two sequences is a function of the number of identical positions shared by the sequences, taking into account the number of gaps, and the length of each gap, which need to be introduced for optimal alignment of the two sequences.

The comparison of sequences and determination of percent identity between two sequences can be accomplished using a mathematical algorithm. In a preferred embodiment, the percent identity between two amino acid sequences is determined using the Needleman and Wunsch ((1970) J. Mol. Biol. 48:444-453) algorithm which has been incorporated into the GAP program in the GCG software package, using either a Blossum 62 matrix or a PAM250 matrix, and a gap weight of 16, 14, 12, 10, 8, 6, or 4 and a length weight of 1, 2, 3, 4, 5, or 6. In yet another preferred embodiment, the percent identity between two nucleotide sequences is determined using the GAP program in the GCG software package, using a NWSgapdna.CMP matrix and a gap weight of 40, 50, 60, 70, or 80 and a length weight of 1, 2, 3, 4, 5, or 6. A particularly preferred set of parameters (and the one that should be used if the practitioner is uncertain about what parameters should be applied to determine if a molecule is within a sequence identity or homology limitation of the invention) are a Blossum 62 scoring matrix with a gap penalty of 12, a gap extend penalty of 4, and a frameshift gap penalty of 5.

As used herein, the term “homologous” is synonymous with “similarity” and means that a sequence of interest differs from a reference sequence by the presence of one or more amino acid substitutions (although modest amino acid insertions or deletions) may also be present. Presently preferred means of calculating degrees of homology or similarity to a reference sequence are through the use of BLAST algorithms (available from the National Center of Biotechnology Information (NCBI), National Institutes of Health, Bethesda Md.), in each case, using the algorithm default or recommended parameters for determining significance of calculated sequence relatedness. The percent identity between two amino acid or nucleotide sequences can also be determined using the algorithm of E. Meyers and W. Miller ((1989) CABIOS, 4:11-17) which has been incorporated into the ALIGN program (version 2.0), using a PAM120 weight residue table, a gap length penalty of 12 and a gap penalty of 4.

As used herein, the term “hybridizes under low stringency, medium stringency, high stringency, or very high stringency conditions” describes conditions for hybridization and washing. Guidance for performing hybridization reactions can be found in Current Protocols in Molecular Biology, John Wiley & Sons, N.Y. (1989), 6.3.1-6.3.6. Aqueous and nonaqueous methods are described in that reference and either can be used. Specific hybridization conditions referred to herein are as follows: 1) low stringency hybridization conditions in 6× sodium chloride/sodium citrate (SSC) at about 45° C., followed by two washes in 0.2×SSC, 0.1% SDS at least at 50° C. (the temperature of the washes can be increased to 55° C. for low stringency conditions); 2) medium stringency hybridization conditions in 6×SSC at about 45° C., followed by one or more washes in 0.2×SSC, 0.1% SDS at 60° C.; 3) high stringency hybridization conditions in 6×SSC at about 45° C., followed by one or more washes in 0.2×SSC, 0.1% SDS at 65° C.; and 4) very high stringency hybridization conditions are 0.5M sodium phosphate, 7% SDS at 65° C., followed by one or more washes at 0.2×SSC, 1% SDS at 65° C.

It is understood that the ligands described herein may have mutations relative to a ligand described herein (e.g., a conservative or non-essential amino acid substitutions), which do not have a substantial effect on the polypeptide functions. Whether or not a particular substitution will be tolerated, i.e., will not adversely affect desired biological properties, such as binding activity can be determined as described in Bowie, et al. (1990) Science 247:1306-1310. A “conservative amino acid substitution” is one in which the amino acid residue is replaced with an amino acid residue having a similar side chain. Families of amino acid residues having similar side chains have been defined in the art. These families include amino acids with basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan), beta-branched side chains (e.g., threonine, valine, isoleucine) and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine). It is possible for framework and CDR amino acid residues to include one or more conservative substitutions.

A “non-essential” amino acid residue is a residue that can be altered from the wild-type sequence of the binding agent, e.g., the antibody, without abolishing or more preferably, without substantially altering a biological activity, whereas an “essential” amino acid residue results in such a change.

Generally, where “X” is used to represent an amino acid residue, any amino acid (e.g., any of the twenty naturally occurring amino acids) can be used at that position, or at least a subset thereof (e.g., any of the nineteen non-cysteine amino acids).

The terms “polypeptide” or “peptide” (which may be used interchangeably) refer to a polymer of three or more amino acids linked by a peptide bond, e.g., between 3 and 30, 12 and 60, or 30 and 300, or over 300 amino acids in length. The polypeptide may include one or more unnatural amino acids. Typically, the polypeptide includes only natural amino acids. A “protein” can include one or more polypeptide chains. Accordingly, the term “protein” encompasses polypeptides. A protein or polypeptide can also include one or more modifications, e.g., a glycosylation, amidation, phosphorylation, and so forth. The term “small peptide” can be used to describe a polypeptide that is between 3 and 30 amino acids in length, e.g., between 8 and 24 amino acids in length.

Statistical significance can be determined by any art known method. Exemplary statistical tests include: the Students T-test, Mann Whitney U non-parametric test, and Wilcoxon non-parametric statistical test. Some statistically significant relationships have a P value of less than 0.05, or 0.02. Particular ligands may show a difference, e.g., in specificity or binding, that are statistically significant (e.g., P value<0.05 or 0.02).

Other features and advantages of the instant invention will become more apparent from the following detailed description and claims. Embodiments of the invention can include any combination of features described herein. The contents of all references, pending patent applications and published patents, cited throughout this application are hereby expressly incorporated by reference.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a bivariant FACS plot showing labelling with the platelet specific marker CD42 with Tie1 and labelling with the E3 antibody. Only a background number of CD42 positive cells are labelled by the E3 antibody.

FIGS. 2A, 2B, 3A, and 3B are plots of the number of branching points verses antibody concentration comparing germlined E3 (3A and 3B) with parental E3 (2A and 2B)

DETAILED DESCRIPTION

This disclosure provides, inter alia, methods for identifying proteins that bind to Tie1 and Tie1 binding proteins. The identified protein may be, for example, a small peptide (e.g., a cyclic or linear peptide, e.g., of between 7 and 25 amino acids), a polypeptide (e.g., a polypeptide of at least 20 amino acids), or a multi-chain protein (e.g., including at least two peptides or polypeptides). An example of a multi-chain protein is an antibody that has separate heavy and light chains. An example of a polypeptide is a single chain antibody.

Tie1 is a receptor tyrosine kinase protein that includes a transmembrane domain. Tie1 is present almost exclusively on endothelial cells. Accordingly, a Tie1 binding ligand can be used, e.g., to specifically recognize or target an endothelial cell. Some Tie1 binding ligands can also be used to agonize or antagonize endothelial cells. In some embodiments, these Tie1-binding ligands have an affinity for particular structural features (e.g., a feature listed below), a combination of features listed below, and/or an epitope that includes at least one amino acid in a structural feature listed below:

Key From To Length Description SIGNAL 1 24 24 POTENTIAL. CHAIN 25 1138 1114 TYROSINE−PROTEIN KINASE RECEPTOR TIE1. DOMAIN 25 759 735 EXTRACELLULAR (POTENTIAL). TRANSMEM 760 784 25 POTENTIAL. DOMAIN 785 1138 354 CYTOPLASMIC (POTENTIAL). DOMAIN 43 105 63 IG-LIKE C2-TYPE 1. DOMAIN 214 256 43 EGF-LIKE 1. DOMAIN 258 303 46 EGF-LIKE 2. DOMAIN 305 345 41 EGF-LIKE 3. DOMAIN 372 426 55 IG-LIKE C2-TYPE 2. DOMAIN 446 540 95 FIBRONECTIN TYPE-III 1. DOMAIN 543 639 97 FIBRONECTIN TYPE-III 2. DOMAIN 643 744 102 FIBRONECTIN TYPE-III 3. DOMAIN 839 1118 280 PROTEIN KINASE. NP_BIND 845 853 9 ATP (BY SIMILARITY). BINDING 870 870 ATP (BY SIMILARITY). ACT_SITE 979 979 BY SIMILARITY. CARBOHYD 83 83 N-LINKED (GLCNAC . . .) (POTENTIAL). CARBOHYD 161 161 N-LINKED (GLCNAC . . .) (POTENTIAL). CARBOHYD 503 503 N-LINKED (GLCNAC . . .) (POTENTIAL). CARBOHYD 596 596 N-LINKED (GLCNAC . . .) (POTENTIAL). CARBOHYD 709 709 N-LINKED (GLCNAC . . .) (POTENTIAL). MOD_RES 1007 1007 PHOSPHORYLATION (AUTO-) (BY SIMILARITY).

The sequence is relative to the amino acid sequence provided in SEQ ID NO:2 (Example 1, below).

One method for identifying proteins that bind to Tie1 includes: providing a library and selecting from the library one or more members that encode a protein that binds to the Tie1 antigen or a fragment thereof (e.g., the extracellular domain, an EGF domain, a fibronectin repeat, or an Ig-superfamily domain (e.g., a Ig-like C2-type 2 domain). The selection can be performed in a number of ways. For example, the library can be a display library.

The Tie1 can be tagged and recombinantly expressed. The Tie1 is purified and attached to a support, e.g., to affinity beads, or paramagnetic beads or other magnetically responsive particles.

The Tie1 can also be expressed on the surface of a cell. Members of the display library that specifically bind to the cell, e.g., only if the Tie1 is activated, can be selected.

Tie1 Agonists and Antagonists

In one embodiment, a Tie1-binding ligand can modulate a Tie1 activity. For example, the Tie1-binding ligand is a Tie1 agonist or antagonist.

Tie1 agonists can be used, e.g., to stimulate an activity of an endothelial cell. For example, a Tie1 agonist can be used to increase phosphatidylinosoitol 3-kinase (PI3 kinase) activity in an endothelial cell and/or Akt kinase activity. Kontos et al. suggest that the cytoplasmic domain of Tie1 can associate with the p85 subunit of PI3 kinase and activate PI3 kinase activity. Kontos (2002) Mol. Cell. Biol. 22:1704-1713. The Tie cytoplasmic domain may also associate with a protein tyrosine phosphatase Shp2. See, e.g., Marron et al. (2000) Adv. Exp. Med. Biol. 476:35-46. A Tie1 agonist may also increase dimerization, and/or tyrosine phosphorylation (e.g., as a result of auto-phosphorylation) of the Tie1 cytoplasmic domain, e.g., the tyrosine in the motif YVN at about amino acid 1117.

Tie1-binding ligand can be evaluated for agonist activity in a cell assay (e.g., in the BaF3 cell assay as described below in Example 2). An exemplary cell assay uses a growth factor dependent cell in which a chimeric receptor that includes the Tie1 ectodomain fused to the intracellular domain of the growth factor receptor is expressed. Cells are evaluated for ability to grow in the absence of the essential growth factor, but in the presence of a test compound, e.g., a Tie1-binding ligand. If the Tie1-binding ligand agonizes Tie1, a signalling activity of the Tie1 chimera can substitute for stimulation by the required growth factor thorough its cognate receptor. Thus, survival of the cell in the absence of the required growth factor can be used as an indication that the Tie1-binding ligand agonizes Tie1.

Tie1 antagonists can be used, e.g., to reduce an activity of an endothelial cell. For example, a Tie1 antagonists can be used to decrease phosphatidylinosoitol 3-kinase (PI3 kinase) activity in an endothelial cell, Shp2 activity, and/or Akt kinase activity. A Tie1 antagonists may also reduce dimerization, and/or tyrosine phosphorylation (e.g., as a result of auto-phosphorylation) of the Tie1 cytoplasmic domain, e.g., the tyrosine in the motif YVN at about amino acid 1117.

Tie1-binding ligand can be evaluated for antagonist activity in a cell assay. For example, the antagonist can be assayed for ability to prevent a Tie1 agonist (such as the E3 antibody) to stimulate Tie1 in a cell assay described herein. (e.g., the BaF3 cell assay as described below in Example 2).

Display Libraries

A number of methods can be used to identify proteins that bind to Tie1. In one embodiment, a display library is used to identify proteins that bind to Tie1. A display library is a collection of entities; each entity includes an accessible protein component and a recoverable component that encodes or identifies the protein component. The protein component can be of any length, e.g. from three amino acids to over 300 amino acids. In a selection, the protein component of each member of the library is probed with Tie1 protein and if the protein component binds to Tie1, the display library member is identified, e.g., by retention on a support.

Retained display library members are recovered from the support and analyzed. The analysis can include amplification and a subsequent selection under similar or dissimilar conditions. For example, positive and negative selections can be alternated. The analysis can also include determining the amino acid sequence of the protein component and purification of the protein component for detailed characterization.

A variety of formats can be used for display libraries. Examples include the following.

Phage Display. One format utilizes viruses, particularly bacteriophages. This format is termed “phage display.” The protein component is typically covalently linked to a bacteriophage coat protein. The linkage results form translation of a nucleic acid encoding the protein component fused to the coat protein. The linkage can include a flexible peptide linker, a protease site, or an amino acid incorporated as a result of suppression of a stop codon. Phage display is described, for example, in Ladner et al., U.S. Pat. No. 5,223,409; Smith (1985) Science 228:1315-1317; WO 92/18619; WO 91/17271; WO 92/20791; WO 92/15679; WO 93/01288; WO 92/01047; WO 92/09690; WO 90/02809; de Haard et al. (1999) J. Biol. Chem. 274:18218-30; Hoogenboom et al. (1998) Immunotechnology 4:1-20; Hoogenboom et al. (2000) Immunol Today 2:371-8; Fuchs et al. (1991) Bio/Technology 9:1370-1372; Hay et al. (1992) Hum Antibod Hybridomas 3:81-85; Huse et al. (1989) Science 246:1275-1281; Griffiths et al. (1993) EMBO J 12:725-734; Hawkins et al. (1992) J Mol Biol 226:889-896; Clackson et al. (1991) Nature 352:624-628; Gram et al. (1992) PNAS 89:3576-3580; Garrard et al. (1991) Bio/Technology 9:1373-1377; Rebar et al. (1996) Methods Enzymol. 267:129-49; Hoogenboom et al. (1991) Nuc Acid Res 19:4133-4137; and Barbas et al. (1991) PNAS 88:7978-7982.

Phage display systems have been developed for filamentous phage (phage f1, fd, and M13) as well as other bacteriophage (e.g. T7 bacteriophage and lambdoid phages; see, e.g., Santini (1998) J. Mol. Biol. 282:125-135; Rosenberg et al. (1996) Innovations 6:1-6; Houshm et al. (1999) Anal Biochem 268:363-370). The filamentous phage display systems typically use fusions to a minor coat protein, such as gene III protein, and gene VIII protein, a major coat protein, but fusions to other coat proteins such as gene VI protein, gene VII protein, gene IX protein, or domains thereof can also been used (see, e.g., WO 00/71694). In one embodiment, the fusion is to a domain of the gene III protein, e.g., the anchor domain or “stump,” (see, e.g., U.S. Pat. No. 5,658,727 for a description of the gene III protein anchor domain). It is also possible to physically associate the protein being displayed to the coat using a non-peptide linkage, e.g., a non-covalent bond or a non-peptide covalent bond. For example, a disulfide bond and/or c-fos and c-jun coiled-coils can be used for physical associations (see, e.g., Crameri et al. (1993) Gene 137:69 and WO 01/05950).

The valency of the protein component can also be controlled. Cloning of the sequence encoding the protein component into the complete phage genome results in multivariant display since all replicates of the gene III protein are fused to the protein component. For reduced valency, a phagemid system can be utilized. In this system, the nucleic acid encoding the protein component fused to gene III is provided on a plasmid, typically of length less than 7000 nucleotides. The plasmid includes a phage origin of replication so that the plasmid is incorporated into bacteriophage particles when bacterial cells bearing the plasmid are infected with helper phage, e.g. M13K01. The helper phage provides an intact copy of gene III and other phage genes required for phage replication and assembly. The helper phage has a defective origin such that the helper phage genome is not efficiently incorporated into phage particles relative to the plasmid that has a wild type origin.

Bacteriophage displaying the protein component can be grown and harvested using standard phage preparatory methods, e.g. PEG precipitation from growth media.

After selection of individual display phages, the nucleic acid encoding the selected protein components, by infecting cells using the selected phages. Individual colonies or plaques can be picked, the nucleic acid isolated and sequenced.

Cell-based Display. In still another format the library is a cell-display library. Proteins are displayed on the surface of a cell, e.g., a eukaryotic or prokaryotic cell. Exemplary prokaryotic cells include E. coli cells, B. subtilis cells, and spores (see, e.g., Lu et al. (1995) Biotechnology 13:366). Exemplary eukaryotic cells include yeast (e.g., Saccharomyces cerevisiae, Schizosaccharomyces pombe, Hanseula, or Pichia pastoris). Yeast surface display is described, e.g., in Boder and Wittrup (1997) Nat. Biotechnol. 15:553-557 and WO 03/029456, which describes a yeast display system that can be used to display immunoglobulin proteins such as Fab fragments and the use of mating to generate combinations of heavy and light chains.

In one embodiment, variegate nucleic acid sequences are cloned into a vector for yeast display. The cloning joins the variegated sequence with a domain (or complete) yeast cell surface protein, e.g., Aga2, Aga1, Flo1, or Gas1. A domain of these proteins can anchor the polypeptide encoded by the variegated nucleic acid sequence by a transmembrane domain (e.g., Flo1) or by covalent linkage to the phospholipid bilayer (e.g., Gas1). The vector can be configured to express two polypeptide chains on the cell surface such that one of the chains is linked to the yeast cell surface protein. For example, the two chains can be immunoglobulin chains.

In one embodiment, nucleic acids encoding immunoglobulin heavy chains that have been mutagenized based on an initial Tie1-binding immunoglobulin are introduced into yeast cells of one cell type, and nucleic acids encoding immunoglobulin light chains that have been mutagenized based on an initial Tie1-binding immunoglobulin are introduced into yeast cells of the other cell type. These two populations of cells can be combined to form diploid yeast that each express an immunoglobulin heavy and light chain. The yeast cells can be selected and/or screened for cells that bind to Tie1, e.g., bind with improved affinity.

Ribosome Display. RNA and the polypeptide encoded by the RNA can be physically associated by stabilizing ribosomes that are translating the RNA and have the nascent polypeptide still attached. Typically, high divalent Mg²⁺ concentrations and low temperature are used. See, e.g., Mattheakis et al. (1994) Proc. Natl. Acad. Sci. USA 91:9022 and Hanes et al. (2000) Nat Biotechnol. 18:1287-92; Hanes et al. (2000) Methods Enzymol. 328:404-30; and Schaffitzel et al. (1999) J Immunol Methods. 231 (1-2):119-35.

Polypeptide-Nucleic Acid Fusions. Another format utilizes polypeptide-nucleic acid fusions. Polypeptide-nucleic acid fusions can be generated by the in vitro translation of mRNA that include a covalently attached puromycin group, e.g., as described in Roberts and Szostak (1997) Proc. Natl. Acad. Sci. USA 94:12297-12302, and U.S. Pat. No. 6,207,446. The mRNA can then be reverse transcribed into DNA and crosslinked to the polypeptide.

Other Display Formats. Yet another display format is a non-biological display in which the protein component is attached to a non-nucleic acid tag that identifies the polypeptide. For example, the tag can be a chemical tag attached to a bead that displays the polypeptide or a radiofrequency tag (see, e.g., U.S. Pat. No. 5,874,214).

Display technology can also be used to obtain ligands, e.g., antibody ligands, particular epitopes of a target. This can be done, for example, by using competing non-target molecules that lack the particular epitope or are mutated within the epitope, e.g., with alanine. Such non-target molecules can be used in a negative selection procedure as described below, as competing molecules when binding a display library to the target, or as a pre-elution agent, e.g., to capture in a wash solution dissociating display library members that are not specific to the target.

Iterative Selection. In one preferred embodiment, display library technology is used in an iterative mode. A first display library is used to identify one or more ligands for a target. These identified ligands are then varied, e.g., using a mutagenesis method, to form a second display library. Higher affinity ligands are then selected from the second library, e.g., by using higher stringency or more competitive binding and washing conditions.

In some implementations, the mutagenesis is targeted to regions known or likely to be at the binding interface. If, for example, the identified ligands are antibodies, then mutagenesis can be directed to the CDR regions of the heavy or light chains as described herein. Further, mutagenesis can be directed to framework regions near or adjacent to the CDRs, e.g., framework regions, particular within ten, five, or three amino acids of a CDR junction. In the case of antibodies, mutagenesis can also be limited to one or a few of the CDRs, e.g., to make precise step-wise improvements.

Some exemplary mutagenesis techniques include: error-prone PCR (Leung et al. (1989) Technique 1:11-15), recombination (see, e.g., U.S. Ser. No. 10/279,633), DNA shuffling using random cleavage (Stemmer (1994) Nature 389-391; termed “nucleic acid shuffling”), RACHITT™ (Coco et al. (2001) Nature Biotech. 19:354), site-directed mutagenesis (Zoller et al. (1987) Nucl Acids Res 10:6487-6504), cassette mutagenesis (Reidhaar-Olson (1991) Methods Enzymol. 208:564-586) and incorporation of degenerate oligonucleotides (Griffiths et al. (1994) EMBO J 13:3245).

In one example of iterative selection, the methods described herein are used to first identify a protein ligand from a display library that binds a Tie1 with at least a minimal binding specificity for a target or a minimal activity, e.g., an equilibrium dissociation constant for binding of greater than 1 nM, 10 nM, or 100 nM. The nucleic acid sequence encoding the initial identified protein ligand are used as a template nucleic acid for the introduction of variations, e.g., to identify a second protein ligand that has enhanced properties (e.g., binding affinity, kinetics, or stability) relative to the initial protein ligand.

Off-Rate Selection. Since a slow dissociation rate can be predictive of high affinity, particularly with respect to interactions between polypeptides and their targets, the methods described herein can be used to isolate ligands with a desired kinetic dissociation rate (i.e. reduced) for a binding interaction to a target.

To select for slow dissociating ligands from a display library, the library is contacted to an immobilized target. The immobilized target is then washed with a first solution that removes non-specifically or weakly bound biomolecules. Then the immobilized target is eluted with a second solution that includes a saturation amount of free target, i.e., replicates of the target that are not attached to the particle. The free target binds to biomolecules that dissociate from the target. Rebinding is effectively prevented by the saturating amount of free target relative to the much lower concentration of immobilized target.

The second solution can have solution conditions that are substantially physiological or that are stringent. Typically, the solution conditions of the second solution are identical to the solution conditions of the first solution. Fractions of the second solution are collected in temporal order to distinguish early from late fractions. Later fractions include biomolecules that dissociate at a slower rate from the target than biomolecules in the early fractions.

Further, it is also possible to recover display library members that remain bound to the target even after extended incubation. These can either be dissociated using chaotropic conditions or can be amplified while attached to the target. For example, phage bound to the target can be contacted to bacterial cells.

Selecting and Screening for Specificity. “Selection” refers to a process in which many members of a display library are allowed to contact the target and those that bind are recovered and propagated. The selection can be from a library having numerous members, e.g., more than 10¹⁰ members. “Screening” refers to a process in which isolated members of the library are tested singly for binding to the target. Through automation, thousands of candidates may be screened in a highly parallel process. The display library selection methods described herein can include a selection process that discards display library members that bind to a non-target molecule. Examples of non-target molecules include, e.g., extracellular domains of molecules that include an immunoglobulin super-family domain or an EGF domain and receptor tyrosine kinases other than Tie1, e.g., Tie2. In one implementation, a so-called “negative selection” step is used to discriminate between the target and related non-target molecule and a related, but distinct non-target molecules. The display library or a pool thereof is contacted to the non-target molecule. Members of the sample that do not bind the non-target are collected and used in subsequent selections for binding to the target molecule or even for subsequent negative selections. The negative selection step can be prior to or after selecting library members that bind to the target molecule.

In another implementation, a screening step is used. After display library members are isolated for binding to the target molecule, each isolated library member is tested for its ability to bind to a non-target molecule (e.g., a non-target listed above). For example, a high-throughput ELISA screen can be used to obtain this data. The ELISA screen can also be used to obtain quantitative data for binding of each library member to the target. The non-target and target binding data are compared (e.g., using a computer and software) to identify library members that specifically bind to Tie1.

The display library selection and screening methods described herein can include a selection or screening process that selects for display library members that bind to specific sites on the target molecule. For example, elution with high concentration of an antibody described herein can be used to select for phage that bind to an epitope that is near or overlaps with the epitope bound by the antibody used for elution. Accordingly, one can screen for a phage that binds to the E3-binding site of Tie1 by performing ELISAs with and without E3 antibody in the buffer.

Selection and Screening for Tie1-Binding Antibodies:

The following provides one exemplary method for identifying antibodies that bind to Tie1 using a phagemid Fab library. For example, three rounds of selection can be performed with decreasing amounts of target protein (e.g., 100, 50 and 50 μg for first, second, and third rounds, respectively). The target is immobilized on streptavidin coated magnetic beads (Dynal). The library is depleted against streptavidin coated magnetic beads prior to each round of selection and optionally against an unrelated protein which may include a common purification handle. For example, if the target is produced as a fusion to a Fc domain, the library can be depleted against soluble Trail-Fc (a commercially available Fc fusion protein). The depletion process removes Fc binders.

Each round of selection can include, e.g., two cycles of streptavidin magnetic bead depletion, a cycle of binding of phage to Tie1-coated beads, ten cycles of washes, elution of bound phage, and propagation of enriched phage for the next round. Phage bound to Tie1-coated beads after ten washes can be directly amplified or eluted before amplification. After three rounds of selection, individual clones may be grown in 96-well microtiter plates and individually screened for Tie1 binding activity by phage ELISA. ELISAs can include evaluations of binding to Tie1, specificity controls, and unrelated controls. Isolates can be DNA fingerprinted to determine the diversity emerging from the selection process. For example, positive isolates can be PCR amplified with the oligonucleotide primers M13-reverse and geneIII-forward (see, e.g., Marks et al. (1991), J. Mol. Biol. 222:581). The products can be analyzed by BstNI fingerprinting.

An exemplary method for performing ELISA's with phage that display a ligand is as follows. Individual clones can be grown and rescued as described previously (Marks et al. (1991), J. Mol. Biol. 222:581). For ELISAs, 96-well Immulon 2 HB plates (Thermo Labsystems) are coated with 1 μg/well ImmunoPure™ streptavidin (Pierce) in PBS and incubated overnight at 4° C. After three washes with PBS, 100 μL of biotinylated Tie1 protein is allowed to bind to the immobilized streptavidin for 30-60 minutes at room temperature. Then, Tie1-coated wells are blocked with 300 μL of 2% milk/1×PBS/0.05% Tween (2% MPBST) for two hours at 37° C. The wells are incubated with 100 μL of phage culture supernatant that had been blocked with 2% MPBST for one hour at room temperature. The wells are washed five times with 1×PBS/Tween 0.1% (PBST), and incubated with 100 mL of anti-M13-HRP secondary antibody at a 1:5,000 dilution for one hour at room temperature. The wells are washed five times with PBST before developing with TMB-solution and read at 630 nm.

For the cell ELISAs, cells are washed once in PBS and resuspended at a concentration of 1×10⁶ to 2×10⁶ cells/mL of PBS. A final concentration of 1-2×10⁵ cells per well of a 96-well tissue culture plate (Falcon, VWR) can be used. The cells are fixed by adding an equal volume of 0.2% glutaraldehyde (Sigma-Aldrich) and incubating at 37° C. for 12 minutes. They are then washed three times with PBS using an automated plate washer (Bio-Tek Instruments, Inc.) and blocked with 200 mL of 2% MPBST for one hour at room temperature. The rest of the ELISA procedure can be performed as described above except that 1×PBS/Tween 0.05% is used for the washes and incubations.

Germlining Antibodies

It is possible to modify an antibody that binds Tie1, e.g., an antibody described herein, in order to make the variable regions of the antibody more similar to one or more germline sequences. For example, an antibody can include one, two, three or more amino acid substitutions, e.g., in a framework or CDR region, to make it more similar to a reference germline sequence. One exemplary germlining method can include: identifying one or more germline sequences that are similar (e.g., most similar in a particular database) to the sequence of the isolated antibody. Then mutations (at the amino acid level) can be made in the isolated antibody, either incrementally, in combination, or both. For example, a nucleic acid library that includes sequences encoding some or all possible germline mutations is made. The mutated antibodies are then evaluated, e.g., to identify an antibody that has one or more additional germline residues relative to the isolated antibody and that is still useful (e.g., has a functional activity). In one embodiment, as many germline residues are introduced into an isolated antibody as possible.

In one embodiment, mutagenesis is used to substitute or insert one or more germline residues into a CDR region. For example, the germline CDR residue can be from a germline sequence that is similar (e.g., most similar) to the variable region being modified. After mutagenesis, activity (e.g., binding or other functional activity) of the antibody can be evaluated to determine if the germline residue or residues are tolerated. Similar mutagenesis can be performed in the framework regions.

Selecting a germline sequence can be performed in different ways. For example, a germline sequence can be selected if it meets a predetermined criteria for selectivity or similarity, e.g., at least a certain percentage identity, e.g., at least 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 99.5% identity. The selection can be performed using at least 2, 3, 5, or 10 germline sequences. In the case of CDR1 and CDR2, identifying a similar germline sequence can include selecting one such sequence. In the case of CDR3, identifying a similar germline sequence can include selecting one such sequence, but may including using two germline sequences that separately contribute to the amino-terminal portion and the carboxy-terminal portion. In other implementations more than one or two germline sequences are used, e.g., to form a consensus sequence.

In one embodiment, with respect to a particular reference variable domain sequence, e.g., a sequence described herein, a related variable domain sequence has at least 30, 40, 50, 60, 70, 80, 90, 95 or 100% of the CDR amino acid positions that are not identical to residues in the reference CDR sequences, residues that are identical to residues at corresponding positions in a human germline sequence (i.e., an amino acid sequence encoded by a human germline nucleic acid).

In one embodiment, with respect to a particular reference variable domain sequence, e.g., a sequence described herein, a related variable domain sequence has at least 30, 50, 60, 70, 80, 90 or 100% of the FR regions are identical to FR sequence from a human germline sequence, e.g., a germline sequence related to the reference variable domain sequence.

Accordingly, it is possible to isolate an antibody which has similar activity to a given antibody of interest, but is more similar to one or more germline sequences, particularly one or more human germline sequences. For example, an antibody can be at least 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.5% identical to a germline sequence in a region outside the CDRs (e.g., framework regions). Further an antibody can include at least 1, 2, 3, 4, or 5 germline residues in a CDR region, the germline residue being from a germline sequence of similar (e.g., most similar) to the variable region being modified. Germline sequences of primary interest are human germline sequences. The activity of the antibody (e.g., the binding activity) can be within a factor or 100, 10, 5, 2, 0.5, 0.1, and 0.001 of the original antibody.

Exemplary germline reference sequences for Vkappa include: O12/O2, O18/O8, A20, A30, L14, L1, L15, L4/18a, L5/L19, L8, L23, L9, L24, L11, L12, O11/O1, A17, A1, A18, A2, A19/A3, A23, A27, All, L2/L16, L6, L20, L25, B3, B2, A26/A10, and A14. See, e.g., Tomlinson et al. (1995) EMBO J. 14 (18):4628-3.

A germline reference sequence for the HC variable domain can be based on a sequence that has particular canonical structures, e.g., 1-3 structures in the H1 and H2 hypervariable loops. The canonical structures of hypervariable loops of an immunoglobulin variable domain can be inferred from its sequence, as described in Chothia et al. (1992) J. Mol. Biol. 227:799-817; Tomlinson et al. (1992) J. Mol. Biol. 227:776-798); and Tomlinson et al. (1995) EMBO J. 14 (18):4628-38. Exemplary sequences with a 1-3 structure include: DP-1, DP-8, DP-12, DP-2, DP-25, DP-15, DP-7, DP-4, DP-31, DP-32, DP-33, DP-35, DP-40, 7-2, hv3005, hv3005f3, DP-46, DP-47, DP-58, DP-49, DP-50, DP-51, DP-53, and DP-54.

Diversity

Display libraries and other libraries include variation at one or more positions in the displayed polypeptide. The variation at a given position can be synthetic or natural. For some libraries, both synthetic and natural diversity are included.

Synthetic Diversity. Libraries can include regions of diverse nucleic acid sequence that originate from artificially synthesized sequences. Typically, these are formed from degenerate oligonucleotide populations that include a distribution of nucleotides at each given position. The inclusion of a given sequence is random with respect to the distribution. One example of a degenerate source of synthetic diversity is an oligonucleotide that includes NNN wherein N is any of the four nucleotides in equal proportion.

Synthetic diversity can also be more constrained, e.g., to limit the number of codons in a nucleic acid sequence at a given trinucleotide to a distribution that is smaller than NNN. For example, such a distribution can be constructed using less than four nucleotides at some positions of the codon. In addition, trinucleotide addition technology can be used to further constrain the distribution.

So-called “trinucleotide addition technology” is described, e.g., in Wells et al. (1985) Gene 34:315-323, U.S. Pat. No. 4,760,025 and U.S. Pat. No. 5,869,644. Oligonucleotides are synthesized on a solid phase support, one codon (i.e., trinucleotide) at a time. The support includes many functional groups for synthesis such that many oligonucleotides are synthesized in parallel. The support is first exposed to a solution containing a mixture of the set of codons for the first position. The unit is protected so additional units are not added. The solution containing the first mixture is washed away and the solid support is deprotected so a second mixture containing a set of codons for a second position can be added to the attached first unit. The process is iterated to sequentially assemble multiple codons. Trinucleotide addition technology enables the synthesis of a nucleic acid that at a given position can encode a number of amino acids. The frequency of these amino acids can be regulated by the proportion of codons in the mixture. Further the choice of amino acids at the given position is not restricted to quadrants of the codon table as is the case if mixtures of single nucleotides are added during the synthesis. Synthetic oligonucleotides including randomized or spiked codons can be also be used for producing a library for an affinity maturation selection.

Natural Diversity. Libraries can include regions of diverse nucleic acid sequence that originate (or are synthesized based on) from different naturally-occurring sequences. An example of natural diversity that can be included in a display library is the sequence diversity present in immune cells (see also below). Nucleic acids are prepared from these immune cells and are manipulated into a format for polypeptide display.

Antibody Display Libraries

In one embodiment, the display library presents a diverse pool of proteins, each of which includes an immunoglobulin domain, e.g., an immunoglobulin variable domain. Display libraries are particular useful, for example for identifying human or “humanized” antibodies that recognize human antigens. Such antibodies can be used as therapeutics to treat human disorders such as endothelial-related disorders, e.g., metastatic cancer. Since the constant and framework regions of the antibody are human, these therapeutic antibodies may avoid themselves being recognized and targeted as antigens. The constant regions are also optimized to recruit effector functions of the human immune system. The in vitro display selection process surmounts the inability of a normal human immune system to generate antibodies against self-antigens.

A typical antibody display library displays a polypeptide that includes a VH domain and a VL domain. An “immunoglobulin domain” refers to a domain from the variable or constant domain of immunoglobulin molecules. Immunoglobulin domains typically contain two β-sheets formed of about seven β-strands, and a conserved disulphide bond (see, e.g., A. F. Williams and A. N. Barclay 1988 Ann. Rev Immunol. 6:381-405). The canonical structures of hypervariable loops of an immunoglobulin variable can be inferred from its sequence, as described in Chothia et al. (1992) J. Mol. Biol. 227:799-817; Tomlinson et al. (1992) J. Mol. Biol. 227:776-798); and Tomlinson et al. (1995) EMBO J. 14 (18):4628-38. The display library can display the antibody as a Fab fragment (e.g., using two polypeptide chains) or a single chain Fv (e.g., using a single polypeptide chain). Other formats can also be used.

As in the case of the Fab and other formats, the displayed antibody can include a constant region as part of a light or heavy chain. In one embodiment, each chain includes one constant region, e.g., as in the case of a Fab. In other embodiments, additional constant regions are displayed.

Antibody libraries can be constructed by a number of processes (see, e.g., de Haard et al. (1999) J. Biol. Chem. 274:18218-30; Hoogenboom et al. (1998) Immunotechnology 4:1-20. and Hoogenboom et al. (2000) Immunol Today 21:371-8). Further, elements of each process can be combined with those of other processes. The processes can be used such that variation is introduced into a single immunoglobulin domain (e.g., VH or VL) or into multiple immunoglobulin domains (e.g., VH and VL). The variation can be introduced into an immunoglobulin variable domain, e.g., in the region of one or more of CDR1, CDR2, CDR3, FR1, FR2, FR3, and FR4, referring to such regions of either and both of heavy and light chain variable domains. In one embodiment, variation is introduced into all three CDRs of a given variable domain. In another preferred embodiment, the variation is introduced into CDR1 and CDR2, e.g., of a heavy chain variable domain. Any combination is feasible. In one process, antibody libraries are constructed by inserting diverse oligonucleotides that encode CDRs into the corresponding regions of the nucleic acid. The oligonucleotides can be synthesized using monomeric nucleotides or trinucleotides. For example, Knappik et al. (2000) J. Mol. Biol. 296:57-86 describe a method for constructing CDR encoding oligonucleotides using trinucleotide synthesis and a template with engineered restriction sites for accepting the oligonucleotides.

In another process, an animal, e.g., a non-human animal, e.g., a rodent, is immunized with the Tie1. The animal is optionally boosted with the antigen to further stimulate the response. Then spleen cells are isolated from the animal, and nucleic acid encoding VH and/or VL domains is amplified and cloned for expression in the display library. The non-human animal can include one or more human immunoglobulin gene sequences. For example, the animal can include a complete human immunoglobulin locus. The animal may also have an inactivated endogenous immunoglobulin locus.

In yet another process, antibody libraries are constructed from nucleic acid amplified from naïve germline immunoglobulin genes (e.g., human genes). The amplified nucleic acid includes nucleic acid encoding the VH and/or VL domain. Sources of immunoglobulin-encoding nucleic acids are described below. Amplification can include PCR, e.g., with primers that anneal to the conserved constant region, or another amplification method.

Nucleic acid encoding immunoglobulin domains or fragments thereof can be obtained from the immune cells of, e.g., a human, a primate, mouse, rabbit, camel, or rodent. In one example, the cells are selected for a particular property. B cells at various stages of maturity can be selected. In another example, the B cells are naïve.

In one embodiment, fluorescent-activated cell sorting (FACS) is used to sort B cells that express surface-bound IgM, IgD, or IgG molecules. Further, B cells expressing different isotypes of IgG can be isolated. In another preferred embodiment, the B or T cell is cultured in vitro. The cells can be stimulated in vitro, e.g., by culturing with feeder cells or by adding mitogens or other modulatory reagents, such as antibodies to CD40, CD40 ligand or CD20, phorbol myristate acetate, bacterial lipopolysaccharide, concanavalin A, phytohemagglutinin or pokeweed mitogen.

In still another embodiment, the cells are isolated from a subject that has an immunological disorder, e.g., systemic lupus erythematosus (SLE), rheumatoid arthritis, vasculitis, Sjogren syndrome, systemic sclerosis, or anti-phospholipid syndrome. The subject can be a human, or an animal, e.g., an animal model for the human disease, or an animal having an analogous disorder. In yet another embodiment, the cells are isolated from a transgenic non-human animal that includes a human immunoglobulin locus.

In one preferred embodiment, the cells have activated a program of somatic hypermutation. Cells can be stimulated to undergo somatic mutagenesis of immunoglobulin genes, for example, by treatment with anti-immunoglobulin, anti-CD40, and anti-CD38 antibodies (see, e.g., Bergthorsdottir et al. (2001) J Immunol. 166:2228). In another embodiment, the cells are naïve.

The nucleic acid encoding an immunoglobulin variable domain can be isolated from a natural repertoire by the following exemplary method. First, RNA is isolated from the immune cell. Full length (i.e., capped) mRNAs are separated (e.g. by dephosphorylating uncapped RNAs with calf intestinal phosphatase). The cap is then removed with tobacco acid pyrophosphatase and reverse transcription is used to produce the cDNAs.

The reverse transcription of the first (antisense) strand can be done in any manner with any suitable primer. See, e.g., de Haard et al. (1999) J. Biol. Chem. 274:18218-30. The primer binding region can be constant among different immunoglobulins, e.g., in order to reverse transcribe different isotypes of immunoglobulin. The primer binding region can also be specific to a particular isotype of immunoglobulin. Typically, the primer is specific for a region that is 3′ to a sequence encoding at least one CDR. In another embodiment, poly-dT primers may be used (and may be preferred for the heavy-chain genes).

A synthetic sequence can be ligated to the 3′ end of the reverse transcribed strand. The synthetic sequence can be used as a primer binding site for binding of the forward primer during PCR amplification after reverse transcription. The use of the synthetic sequence can obviate the need to use a pool of different forward primers to fully capture the available diversity.

The variable domain-encoding gene is then amplified, e.g., using one or more rounds. If multiple rounds are used, nested primers can be used for increased fidelity. The amplified nucleic acid is then cloned into a display library vector.

Any method for amplifying nucleic acid sequences may be used for amplification. Methods that maximize and do not bias diversity are preferred. A variety of techniques can be used for nucleic acid amplification. The polymerase chain reaction (PCR; U.S. Pat. Nos. 4,683,195 and 4,683,202, Saiki, et al. (1985) Science 230, 1350-1354) utilizes cycles of varying temperature to drive rounds of nucleic acid synthesis. Transcription-based methods utilize RNA synthesis by RNA polymerases to amplify nucleic acid (U.S. Pat. No. 6,066,457; U.S. Pat. No. 6,132,997; U.S. Pat. No. 5,716,785; Sarkar et. al., Science (1989) 244: 331-34; Stofler et al., Science (1988) 239: 491). NASBA (U.S. Pat. Nos. 5,130,238; 5,409,818; and 5,554,517) utilizes cycles of transcription, reverse-transcription, and RNaseH-based degradation to amplify a DNA sample. Still other amplification methods include rolling circle amplification (RCA; U.S. Pat. Nos. 5,854,033 and 6,143,495) and strand displacement amplification (SDA; U.S. Pat. Nos. 5,455,166 and 5,624,825).

Secondary Screening Methods

After selecting candidate display library members that bind to a target, each candidate display library member can be further analyzed, e.g., to further characterize its binding properties for the target. Similarly candidate ligands (e.g., by immunization, etc.) obtained by other methods can also be analyzed. Each candidate ligand can be subjected to one or more secondary screening assays. The assay can be for a binding property, a catalytic property, a physiological property (e.g., cytotoxicity, renal clearance, immunogenicity), a structural property (e.g., stability, conformation, oligomerization state) or another functional property. The same assay can be used repeatedly, but with varying conditions, e.g., to determine pH, ionic, or thermal sensitivities.

As appropriate, the assays can use the display library member directly, a recombinant polypeptide produced from the nucleic acid encoding a displayed polypeptide, or a synthetic peptide synthesized based on the sequence of a displayed polypeptide. Exemplary assays for binding properties include the following.

ELISA. Proteins encoded by a display library can also be screened for a binding property using an ELISA assay. For example, each protein is contacted to a microtitre plate whose bottom surface has been coated with the target, e.g., a limiting amount of the target. The plate is washed with buffer to remove non-specifically bound polypeptides. Then the amount of the protein bound to the plate is determined by probing the plate with an antibody that can recognize the polypeptide, e.g., a tag or constant portion of the polypeptide. The antibody is linked to an enzyme such as alkaline phosphatase, which produces a colorimetric product when appropriate substrates are provided. The protein can be purified from cells or assayed in a display library format, e.g., as a fusion to a filamentous bacteriophage coat. Alternatively, cells (e.g., live or fixed) that express the target molecule, e.g., Tie1, can be plated in a microtitre plate and used to test the affinity of the peptides/antibodies present in the display library or obtained by selection from the display library.

In another version of the ELISA assay, each polypeptide of a diversity strand library is used to coat a different well of a microtitre plate. The ELISA then proceeds using a constant target molecule to query each well.

Cell Binding Assays. Tie1-binding proteins can be evaluated for their ability to interact with one or more cell types, e.g., endothelial cells or platelets. Fluorescent activated cell sorting (FACS) is one exemplary method for testing an interaction between a protein and a cell. The Tie1 binding protein is labeled directly or indirectly with a fluorophore, before or after, binding to the cells, and then cells are counted in a FACS sorter.

For example, the following method can be used to evaluate whether a Tie1 binding protein interacts with platelets or other cell types.

Isolation of Platelets. Human blood can be obtained from informed healthy volunteers. For example, venous blood is collected into one-sixth volume of ACD (2.5 g of sodium citrate, 1.5 g citric acid, and 2.5 g glucose in 100 ml dH₂O). The blood is centrifuged at 800×g for 15 min at room temperature and the platelet-rich plasma is removed and incubated for 60 min at 37° C. in the presence of 1 mM acetylsalicylic acid followed by centrifugation at 1000.times.g for 10 min at room temperature. The platelet pellet can be resuspended at a density of 2·10⁸ cells/ml with HEPES-buffered Tyrode's solution (137 mM NaCl, 2.7 mM KCl, 1 mM MgCl₂, 3 mM NaH₂PO₄, 5 mM glucose, 10 mM HEPES pH 7.4, 0.2% bovine serum albumin, and 0.05 U/mL apyrase). See also, e.g., Kornecki et al. (1990) J Biol. Chem. 265:10,042-10,048 and Naik et al. (1995) Biochem J. 310:155-162).

FACS. For FACS analysis of platelets. Cells can be resuspended in 0.1% BSA/PBS (4×10⁵ cells/sample) in the presence of PGE1 (1 mg/mL) and incubated with the Tie1 ligand (e.g., at about 5 μg/mL) or with a control. After a 1-hour incubation at 22° C., the cells are washed with 0.1% BSA/PBS, treated with 50 μL 1/100 diluted FITC-labeled secondary antibody, incubated for 30 minutes on ice, washed, and resuspended in 0.1% BSA/PBS. The samples are analyzed using an Immunocytometry Systems flow cytometer (FAC Sort, Becton Dickinson, San Jose, Calif.). See also, e.g., Malgorzata et al. (2000) Blood, Vol. 95 No. 8 (April 15 pp. 2600-2609.

In addition, it is possible to evaluate platelets by Westerns analysis of SDS-page separated proteins from isolated platelets and by immunoprecipitation. Still other methods involve binding cells to surfaces to which the Tie1 binding ligand is attached (e.g., coated to).

Other cell types can be prepared for FACS by methods known in the art.

Homogeneous Binding Assays. The binding interaction of candidate polypeptide with a target can be analyzed using a homogenous assay, i.e., after all components of the assay are added, additional fluid manipulations are not required. For example, fluorescence resonance energy transfer (FRET) can be used as a homogenous assay (see, for example, Lakowicz et al., U.S. Pat. No. 5,631,169; Stavrianopoulos, et al., U.S. Pat. No. 4,868,103). A fluorophore label on the first molecule (e.g., the molecule identified in the fraction) is selected such that its emitted fluorescent energy can be absorbed by a fluorescent label on a second molecule (e.g., the target) if the second molecule is in proximity to the first molecule. The fluorescent label on the second molecule fluoresces when it absorbs to the transferred energy. Since the efficiency of energy transfer between the labels is related to the distance separating the molecules, the spatial relationship between the molecules can be assessed. In a situation in which binding occurs between the molecules, the fluorescent emission of the ‘acceptor’ molecule label in the assay should be maximal. A binding event that is configured for monitoring by FRET can be conveniently measured through standard fluorometric detection means well known in the art (e.g., using a fluorimeter). By titrating the amount of the first or second binding molecule, a binding curve can be generated to estimate the equilibrium binding constant.

Another example of a homogenous assay is Alpha Screen (Packard Bioscience, Meriden Conn.). Alpha Screen uses two labeled beads. One bead generates singlet oxygen when excited by a laser. The other bead generates a light signal when singlet oxygen diffuses from the first bead and collides with it. The signal is only generated when the two beads are in proximity. One bead can be attached to the display library member, the other to the target. Signals are measured to determine the extent of binding.

The homogenous assays can be performed while the candidate polypeptide is attached to the display library vehicle, e.g., a bacteriophage.

Surface Plasmon Resonance (SPR). The binding interaction of a molecule isolated from a display library and a target can be analyzed using SPR. SPR or Biomolecular Interaction Analysis (BIA) detects biospecific interactions in real time, without labeling any of the interactants. Changes in the mass at the binding surface (indicative of a binding event) of the BIA chip result in alterations of the refractive index of light near the surface (the optical phenomenon of surface plasmon resonance (SPR)). The changes in the refractivity generate a detectable signal, which are measured as an indication of real-time reactions between biological molecules. Methods for using SPR are described, for example, in U.S. Pat. No. 5,641,640; Raether (1988) Surface Plasmons Springer Verlag; Sjolander and Urbaniczky (1991) Anal. Chem. 63:2338-2345; Szabo et al. (1995) Curr. Opin. Struct. Biol. 5:699-705 and on-line resources provide by BIAcore International AB (Uppsala, Sweden).

Information from SPR can be used to provide an accurate and quantitative measure of the equilibrium dissociation constant (K_(d)), and kinetic parameters, including K_(on) and K_(off), for the binding of a biomolecule to a target. Such data can be used to compare different biomolecules. For example, proteins encoded by nucleic acid selected from a library of diversity strands can be compared to identify individuals that have high affinity for the target or that have a slow K_(off). This information can also be used to develop structure-activity relationships (SAR). For example, the kinetic and equilibrium binding parameters of matured versions of a parent protein can be compared to the parameters of the parent protein. Variant amino acids at given positions can be identified that correlate with particular binding parameters, e.g., high affinity and slow K_(off). This information can be combined with structural modeling (e.g., using homology modeling, energy minimization, or structure determination by crystallography or NMR). As a result, an understanding of the physical interaction between the protein and its target can be formulated and used to guide other design processes.

Protein Arrays. Proteins identified from the display library can be immobilized on a solid support, for example, on a bead or an array. For a protein array, each of the polypeptides is immobilized at a unique address on a support. Typically, the address is a two-dimensional address. Protein arrays are described below (see, e.g., Diagnostics). It is also possible to use a protein array to evaluate any plurality of proteins, e.g., for interaction with Tie1.

Cellular Assays. Candidate proteins can be selected from a library by transforming the library into a host cell; the library could have been previously identified from a display library. For example, the library can include vector nucleic acid sequences that include segments that encode the polypeptides and that direct expression, e.g., such that the proteins are produced within the cell, secreted from the cell, or attached to the cell surface. The cells can be screened or selected for proteins that bind to the Tie1, e.g., as detected by a change in a cellular phenotype or a cell-mediated activity. For example, in the case of an antibody that binds to Tie1, the activity may be autophosphorylation, activation of PI3 Kinase, activation of AKT, or a change in endothelial cell activity (e.g., proliferation).

In another embodiment, the library of cells is in the form of a cellular array. The cellular array can likewise be screened for any appropriate detectable activity.

In other embodiments, competition binding assays are used to identify proteins that are compete with a reference ligand for binding to Tie1. Similarly, epitope mapping can be used to identify proteins that bind to a particular epitope of Tie. Fragments and mutants of Tie1 can be also be used in the ligand-identification process, e.g., in one or more of characterization, screening, or immunization.

Methods for Obtaining Tie1-Binding Antibodies

In addition to the use of display libraries, other methods can be used to obtain a Tie1-binding antibody or in combination with the use of display libraries. For example, the Tie1 ectodomain or a region thereof can be used as an antigen in a non-human animal, e.g., a rodent.

In one embodiment, the non-human animal includes at least a part of a human immunoglobulin gene. For example, it is possible to engineer mouse strains deficient in mouse antibody production with large fragments of the human Ig loci. Using the hybridoma technology, antigen-specific Mabs derived from the genes with the desired specificity may be produced and selected. See, e.g., XenoMouse™, Green et al. Nature Genetics 7:13-21 (1994), U.S. 20030070185, WO 96/34096, published Oct. 31, 1996, and PCT Application No. PCT/US96/05928, filed Apr. 29, 1996.

In another embodiment, a monoclonal antibody is obtained from the non-human animal, and then modified, e.g., humanized or deimmunized. Winter describes a CDR-grafting method that may be used to prepare the humanized antibodies of the present invention (UK Patent Application GB 2188638A, filed on Mar. 26, 1987; Winter U.S. Pat. No. 5,225,539. All of the CDRs of a particular human antibody may be replaced with at least a portion of a non-human CDR or only some of the CDRs may be replaced with non-human CDRs. It is only necessary to replace the number of CDRs required for binding of the humanized antibody to a predetermined antigen.

Humanized antibodies can be generated by replacing sequences of the Fv variable region that are not directly involved in antigen binding with equivalent sequences from human Fv variable regions. General methods for generating humanized antibodies are provided by Morrison, S. L., 1985, Science 229:1202-1207, by Oi et al., 1986, BioTechniques 4:214, and by Queen et al. U.S. Pat. No. 5,585,089, U.S. Pat. No. 5,693,761 and U.S. Pat. No. 5,693,762. Those methods include isolating, manipulating, and expressing the nucleic acid sequences that encode all or part of immunoglobulin Fv variable regions from at least one of a heavy or light chain. Sources of such nucleic acid are well known to those skilled in the art and, for example, may be obtained from a hybridoma producing an antibody against a predetermined target, as described above. The recombinant DNA encoding the humanized antibody, or fragment thereof, can then be cloned into an appropriate expression vector.

A Tie1-binding antibody may also be modified by specific deletion of human T cell epitopes or “deimmunization” by the methods disclosed in WO 98/52976 and WO 00/34317, the contents of which are specifically incorporated by reference herein. Briefly, the heavy and light chain variable regions of an antibody can be analyzed for peptides that bind to MHC Class II; these peptides represent potential T-cell epitopes (as defined in WO 98/52976 and WO 00/34317). For detection of potential T-cell epitopes, a computer modeling approach termed “peptide threading” can be applied, and in addition a database of human MHC class II binding peptides can be searched for motifs present in the VH and VL sequences, as described in WO 98/52976 and WO 00/34317. These motifs bind to any of the 18 major MHC class II DR allotypes, and thus constitute potential T cell epitopes. Potential T-cell epitopes detected can be eliminated by substituting small numbers of amino acid residues in the variable regions, or preferably, by single amino acid substitutions. As far as possible conservative substitutions are made, often but not exclusively, an amino acid common at this position in human germline antibody sequences may be used. Human germline sequences are disclosed in Tomlinson, I. A. et al. (1992) J. Mol. Biol. 227:776-798; Cook, G. P. et al. (1995) Immunol. Today Vol. 16 (5): 237-242; Chothia, D. et al. (1992) J. Mol. Bio. 227:799-817. The V BASE directory provides a comprehensive directory of human immunoglobulin variable region sequences (compiled by Tomlinson, I. A. et al. MRC Centre for Protein Engineering, Cambridge, UK). After the deimmunizing changes are identified, nucleic acids encoding VH and VL can be constructed by mutagenesis or other synthetic methods (e.g., de novo synthesis, cassette replacement, and so forth). Mutagenized variable sequence can, optionally, be fused to a human constant region, e.g., human IgG1 or κ constant regions.

In some cases a potential T cell epitope will include residues which are known or predicted to be important for antibody function. For example, potential T cell epitopes are usually biased towards the CDRs. In addition, potential T cell epitopes can occur in framework residues important for antibody structure and binding. Changes to eliminate these potential epitopes will in some cases require more scrutiny, e.g., by making and testing chains with and without the change. Where possible, potential T cell epitopes that overlap the CDRs were eliminated by substitutions outside the CDRs. In some cases, an alteration within a CDR is the only option, and thus variants with and without this substitution should be tested. In other cases, the substitution required to remove a potential T cell epitope is at a residue position within the framework that might be critical for antibody binding. In these cases, variants with and without this substitution should be tested. Thus, in some cases several variant deimmunized heavy and light chain variable regions were designed and various heavy/light chain combinations tested in order to identify the optimal deimmunized antibody. The choice of the final deimmunized antibody can then be made by considering the binding affinity of the different variants in conjunction with the extent of deimmunization, i.e., the number of potential T cell epitopes remaining in the variable region. Deimmunization can be used to modify an antibody that includes a non-human sequence, e.g., a murine antibody or other non-human monoclonal antibody. Deimmunization can be used to modify an antibody isolated from a display library.

Endothelial Cell Assays

A Tie1-binding ligand or a candidate ligand can be characterized using a cellular assay, e.g., to evaluate a change in a cellular phenotype or other activity when the ligand is contacted to the cell. Typically the cell is expresses a protein that includes at least part of the ectodomain of Tie. In some embodiments, the cell expresses a full-length, mature Tie1 protein.

Endothelial cell proliferation. A candidate Tie1-binding ligand can be tested for endothelial proliferation inhibiting activity using a biological activity assay such as the bovine capillary endothelial cell proliferation assay, the chick CAM assay, the mouse corneal assay, and evaluating the effect of the ligand on implanted tumors. The chick CAM assay is described, e.g., by O'Reilly, et al. in “Angiogenic Regulation of Metastatic Growth” Cell, vol. 79 (2), Oct. 21, 1994, pp. 315-328. Briefly, three day old chicken embryos with intact yolks are separated from the egg and placed in a petri dish. After three days of incubation a methylcellulose disc containing the protein to be tested is applied to the CAM of individual embryos. After 48 hours of incubation, the embryos and CAMs are observed to determine whether endothelial growth has been inhibited. The mouse corneal assay involves implanting a growth factor-containing pellet, along with another pellet containing the suspected endothelial growth inhibitor, in the cornea of a mouse and observing the pattern of capillaries that are elaborated in the cornea.

Angiogenesis. Angiogenesis may be assayed, e.g., using various human endothelial cell systems, such as umbilical vein, coronary artery, or dermal cells. Suitable assays include Alamar Blue based assays (available from Biosource International) to measure proliferation; migration assays using fluorescent molecules, such as the use of Becton Dickinson Falcon HTS FluoroBlock cell culture inserts to measure migration of cells through membranes in presence or absence of angiogenesis enhancer or suppressors; and tubule formation assays based on the formation of tubular structures by endothelial cells on Matrigel™ (Becton Dickinson).

Cell adhesion. Cell adhesion assays measure adhesion of cells to purified adhesion proteins or adhesion of cells to each other, in presence or absence of candidate Tie1 binding ligands. Cell-protein adhesion assays measure the ability of agents to modulate the adhesion of cells to purified proteins. For example, recombinant proteins are produced, diluted to 2.5 g/mL in PBS, and used to coat the wells of a microtiter plate. The wells used for negative control are not coated. Coated wells are then washed, blocked with 1% BSA, and washed again. Compounds are diluted to 2.times. final test concentration and added to the blocked, coated wells. Cells are then added to the wells, and the unbound cells are washed off. Retained cells are labeled directly on the plate by adding a membrane-permeable fluorescent dye, such as calcein-AM, and the signal is quantified in a fluorescent microplate reader.

Cell-cell adhesion assays can be used to measure the ability of candidate Tie1 binding ligands to modulate binding of cells to each other. These assays can use cells that naturally or recombinantly express an adhesion protein of choice. In an exemplary assay, cells expressing the cell adhesion protein are plated in wells of a multiwell plate together with other cells (either more of the same cell type, or another type of cell to which the cells adhere). The cells that can adhere are labeled with a membrane-permeable fluorescent dye, such as BCECF, and allowed to adhere to the monolayers in the presence of candidate ligands. Unbound cells are washed off, and bound cells are detected using a fluorescence plate reader. High-throughput cell adhesion assays have also been described. See, e.g., Falsey J R et al., Bioconjug Chem. May-June 2001; 12 (3):346-53.

Tubulogenesis. Tubulogenesis assays can be used to monitor the ability of cultured cells, generally endothelial cells, to form tubular structures on a matrix substrate, which generally simulates the environment of the extracellular matrix. Exemplary substrates include Matrigel™ (Becton Dickinson), an extract of basement membrane proteins containing laminin, collagen IV, and heparin sulfate proteoglycan, which is liquid at 4° C. and forms a solid gel at 37° C. Other suitable matrices comprise extracellular components such as collagen, fibronectin, and/or fibrin. Cells are stimulated with a pro-angiogenic stimulant, and their ability to form tubules is detected by imaging. Tubules can generally be detected after an overnight incubation with stimuli, but longer or shorter time frames may also be used. Tube formation assays are well known in the art (e.g., Jones M K et al., 1999, Nature Medicine 5:1418-1423). These assays have traditionally involved stimulation with serum or with the growth factors FGF or VEGF. In one embodiment, the assay is performed with cells cultured in serum free medium. In one embodiment, the assay is performed in the presence of one or more pro-angiogenic agents, e.g., inflammatory angiogenic factors such as TNF-α, or FGF, VEGF, phorbol myristate acetate (PMA), TNF-alpha, ephrin, etc.

Cell Migration. An exemplary assay for endothelial cell migration is the human microvascular endothelial (HMVEC) migration assay. See, e.g., Tolsma et al. (1993) J. Cell Biol 122, 497-511. Migration assays are known in the art (e.g., Paik J H et al., 2001, J Biol Chem 276:11830-11837). In one example, cultured endothelial cells are seeded onto a matrix-coated porous lamina, with pore sizes generally smaller than typical cell size. The lamina is typically a membrane, such as the transwell polycarbonate membrane (Corning Costar Corporation, Cambridge, Mass.), and is generally part of an upper chamber that is in fluid contact with a lower chamber containing pro-angiogenic stimuli. Migration is generally assayed after an overnight incubation with stimuli, but longer or shorter time frames may also be used. Migration is assessed as the number of cells that crossed the lamina, and may be detected by staining cells with hemotoxylin solution (VWR Scientific), or by any other method for determining cell number. In another exemplary set up, cells are fluorescently labeled and migration is detected using fluorescent readings, for instance using the Falcon HTS FluoroBlok (Becton Dickinson). While some migration is observed in the absence of stimulus, migration is greatly increased in response to pro-angiogenic factors. The assay can be used to test the effect of a Tie1-binding ligand on endothelial cell migration.

Sprouting assay. An exemplary sprouting assay is a three-dimensional in vitro angiogenesis assay that uses a cell-number defined spheroid aggregation of endothelial cells (“spheroid”), embedded in a collagen gel-based matrix. The spheroid can serve as a starting point for the sprouting of capillary-like structures by invasion into the extracellular matrix (termed “cell sprouting”) and the subsequent formation of complex anastomosing networks (Korff and Augustin, 1999, J Cell Sci 112:3249-58). In an exemplary experimental set-up, spheroids are prepared by pipetting 400 human umbilical vein endothelial cells into individual wells of a nonadhesive 96-well plates to allow overnight spheroidal aggregation (Korff and Augustin: J Cell Biol 143: 1341-52, 1998). Spheroids are harvested and seeded in 900 μl of methocel-collagen solution and pipetted into individual wells of a 24 well plate to allow collagen gel polymerization. Test agents are added after 30 min by pipetting 100 μl of 10-fold concentrated working dilution of the test substances on top of the gel. Plates are incubated at 37° C. for 24 h. Dishes are fixed at the end of the experimental incubation period by addition of paraformaldehyde. Sprouting intensity of endothelial cells can be quantitated by an automated image analysis system to determine the cumulative sprout length per spheroid.

In some embodiments, a Tie1 binding ligand as a statistically significant effect on an assay described herein, e.g., a cellular assay described herein.

Ligand Production

Standard recombinant nucleic acid methods can be used to express a protein ligand that binds to Tie1. See, for example, the techniques described in Sambrook & Russell, Molecular Cloning: A Laboratory Manual, 3^(th) Edition, Cold Spring Harbor Laboratory, N.Y. (2001) and Ausubel et al., Current Protocols in Molecular Biology (Greene Publishing Associates and Wiley Interscience, N.Y. (1989). Generally, a nucleic acid sequence encoding the protein ligand is cloned into a nucleic acid expression vector. If the protein includes multiple polypeptide chains, each chain can be cloned into an expression vector, e.g., the same or different vectors, that are expressed in the same or different cells. Methods for producing antibodies are also provided below.

Antibody Production. Some antibodies, e.g., Fabs, can be produced in bacterial cells, e.g., E. coli cells. For example, if the Fab is encoded by sequences in a phage display vector that includes a suppressible stop codon between the display entity and a bacteriophage protein (or fragment thereof), the vector nucleic acid can be shuffled into a bacterial cell that cannot suppress a stop codon. In this case, the Fab is not fused to the gene III protein and is secreted into the media.

Antibodies can also be produced in eukaryotic cells. In one embodiment, the antibodies (e.g., scFv's) are expressed in a yeast cell such as Pichia (see, e.g., Powers et al. (2001) J Immunol Methods. 251:123-35), Hanseula, or Saccharomyces.

In one embodiment, antibodies are produced in mammalian cells. Preferred mammalian host cells for expressing the clone antibodies or antigen-binding fragments thereof include Chinese Hamster Ovary (CHO cells) (including dhfr− CHO cells, described in Urlaub and Chasin (1980) Proc. Natl. Acad. Sci. USA 77:4216-4220, used with a DHFR selectable marker, e.g., as described in Kaufman and Sharp (1982) Mol. Biol. 159:601-621), lymphocytic cell lines, e.g., NS0 myeloma cells and SP2 cells, COS cells, and a cell from a transgenic animal, e.g., a transgenic mammal. For example, the cell is a mammary epithelial cell.

In addition to the nucleic acid sequence encoding the immunoglobulin domain, the recombinant expression vectors may carry additional sequences, such as sequences that regulate replication of the vector in host cells (e.g., origins of replication) and selectable marker genes. The selectable marker gene facilitates selection of host cells into which the vector has been introduced (see e.g., U.S. Pat. Nos. 4,399,216, 4,634,665 and 5,179,017). For example, typically the selectable marker gene confers resistance to drugs, such as G418, hygromycin or methotrexate, on a host cell into which the vector has been introduced. Preferred selectable marker genes include the dihydrofolate reductase (DHFR) gene (for use in dhfr⁻ host cells with methotrexate selection/amplification) and the neo gene (for G418 selection).

In an exemplary system for recombinant expression of an antibody, or antigen-binding portion thereof, of the invention, a recombinant expression vector encoding both the antibody heavy chain and the antibody light chain is introduced into dhfr− CHO cells by calcium phosphate-mediated transfection. Within the recombinant expression vector, the antibody heavy and light chain genes are each operatively linked to enhancer/promoter regulatory elements (e.g., derived from SV40, CMV, adenovirus and the like, such as a CMV enhancer/AdMLP promoter regulatory element or an SV40 enhancer/AdMLP promoter regulatory element) to drive high levels of transcription of the genes. The recombinant expression vector also carries a DHFR gene, which allows for selection of CHO cells that have been transfected with the vector using methotrexate selection/amplification. The selected transformant host cells are cultured to allow for expression of the antibody heavy and light chains and intact antibody is recovered from the culture medium. Standard molecular biology techniques are used to prepare the recombinant expression vector, transfect the host cells, select for transformants, culture the host cells and recover the antibody from the culture medium. For example, some antibodies can be isolated by affinity chromatography with a Protein A or Protein G.

For antibodies that include an Fc domain, the antibody production system preferably synthesizes antibodies in which the Fc region is glycosylated. For example, the Fc domain of IgG molecules is glycosylated at asparagine 297 in the CH2 domain. This asparagine is the site for modification with biantennary-type oligosaccharides. It has been demonstrated that this glycosylation is required for effector functions mediated by Fcγ receptors and complement Clq (Burton and Woof (1992) Adv. Immunol. 51:1-84; Jefferis et al. (1998) Immunol. Rev. 163:59-76). In a preferred embodiment, the Fc domain is produced in a mammalian expression system that appropriately glycosylates the residue corresponding to asparagine 297. The Fc domain can also include other eukaryotic post-translational modifications.

Antibodies can also be produced by a transgenic animal. For example, U.S. Pat. No. 5,849,992 describes a method of expressing an antibody in the mammary gland of a transgenic mammal. A transgene is constructed that includes a milk-specific promoter and nucleic acids encoding the antibody of interest and a signal sequence for secretion. The milk produced by females of such transgenic mammals includes, secreted-therein, the antibody of interest. The antibody can be purified from the milk, or for some applications, used directly.

It is also possible to produce antibodies that bind to Tie1 by immunization, e.g., using an animal, e.g., with natural, human, or partially human immunoglobulin loci. Non-human antibodies can also be modified to include substitutions for human immunoglobulin sequences, e.g., consensus human amino acid residues at particular positions, e.g., at one or more of the following positions (preferably at least five, ten, twelve, or all): (in the FR of the variable domain of the light chain) 4L, 35L, 36L, 38L, 43L, 44L, 58L, 46L, 62L, 63L, 64L, 65L, 66L, 67L, 68L, 69L, 70L, 71L, 73L, 85L, 87L, 98L, and/or (in the FR of the variable domain of the heavy chain) 2H, 4H, 24H, 36H, 37H, 39H, 43H, 45H, 49H, 58H, 60H, 67H, 68H, 69H, 70H, 73H, 74H, 75H, 78H, 91H, 92H, 93H, and/or 103H (according to the Kabat numbering). See, e.g., U.S. Pat. No. 6,407,213.

Tie1 production. Method for producing Tie1 ectodomain protein, Tie1 protein, or Tie1 liposomes are known in the art. See, e.g., WO 93/14124.

Biotinylation Methods. A variety of methods are available to biotinylate proteins, e.g., an immunoglobulin protein or a target protein. For example, the protein can be incubated with a 5-fold molar excess of sulfo-NHS-SS-biotin in 50 mM HEPES, pH 8.0, 100 mM NaCl overnight at 4° C. Free biotin is removed by buffer exchange into PBS, 0.01% Tween 20, e.g., using a Biomax device with a 10 kDa molecular weight cut-off membrane or by dialysis. The number of biotin molecules incorporated per mole of protein can be determined using the HABA assay as described by the manufacturer (Pierce).

Pharmaceutical Compositions

In another aspect, the invention provides compositions, e.g., pharmaceutically acceptable compositions, which include an Tie1-binding ligand, e.g., an antibody molecule, other polypeptide or peptide identified as binding to Tie1, or described herein, formulated together with a pharmaceutically acceptable carrier. As used herein, “pharmaceutical compositions” encompass labeled ligands (e.g., for in vivo imaging) as well as therapeutic compositions.

As used herein, “pharmaceutically acceptable carrier” includes any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption delaying agents, and the like that are physiologically compatible. Preferably, the carrier is suitable for intravenous, intramuscular, subcutaneous, parenteral, spinal or epidermal administration (e.g., by injection or infusion). Depending on the route of administration, the active compound, i.e., protein ligand may be coated in a material to protect the compound from the action of acids and other natural conditions that may inactivate the compound.

A “pharmaceutically acceptable salt” refers to a salt that retains the desired biological activity of the parent compound and does not impart any undesired toxicological effects (see e.g., Berge, S. M., et al. (1977) J. Pharm. Sci. 66:1-19). Examples of such salts include acid addition salts and base addition salts. Acid addition salts include those derived from nontoxic inorganic acids, such as hydrochloric, nitric, phosphoric, sulfuric, hydrobromic, hydroiodic, phosphorous and the like, as well as from nontoxic organic acids such as aliphatic mono- and dicarboxylic acids, phenyl-substituted alkanoic acids, hydroxy alkanoic acids, aromatic acids, aliphatic and aromatic sulfonic acids and the like. Base addition salts include those derived from alkaline earth metals, such as sodium, potassium, magnesium, calcium and the like, as well as from nontoxic organic amines, such as N,N′-dibenzylethylenediamine, N-methylglucamine, chloroprocaine, choline, diethanolamine, ethylenediamine, procaine and the like.

The compositions of this invention may be in a variety of forms. These include, for example, liquid, semi-solid and solid dosage forms, such as liquid solutions (e.g., injectable and infusible solutions), dispersions or suspensions, tablets, pills, powders, liposomes and suppositories. The preferred form depends on the intended mode of administration and therapeutic application. Typical preferred compositions are in the form of injectable or infusible solutions, such as compositions similar to those used for administration of humans with antibodies. The preferred mode of administration is parenteral (e.g., intravenous, subcutaneous, intraperitoneal, intramuscular). In a preferred embodiment, the Tie1-binding ligand is administered by intravenous infusion or

injection. In another preferred embodiment, the Tie1-binding ligand is administered by intramuscular or subcutaneous injection.

The phrases “parenteral administration” and “administered parenterally” as used herein means modes of administration other than enteral and topical administration, usually by injection, and includes, without limitation, intravenous, intramuscular, intraarterial, intrathecal, intracapsular, intraorbital, intracardiac, intradermal, intraperitoneal, transtracheal, subcutaneous, subcuticular, intraarticular, subcapsular, subarachnoid, intraspinal, epidural and intrasternal injection and infusion.

Pharmaceutical compositions typically must be sterile and stable under the conditions of manufacture and storage. A pharmaceutical composition can also be tested to insure it meets regulatory and industry standards for administration. For example, endotoxin levels in the preparation can be tested using the Limulus amebocyte lysate assay (e.g., using the kit from Bio Whittaker lot # 7L3790, sensitivity 0.125 EU/mL) according to the USP 24/NF 19 methods. Sterility of pharmaceutical compositions can be determined using thioglycollate medium according to the USP 24/NF 19 methods. For example, the preparation is used to inoculate the thioglycollate medium and incubated at 35° C. for 14 or more days. The medium is inspected periodically to detect growth of a microorganism.

The composition can be formulated as a solution, microemulsion, dispersion, liposome, or other ordered structure suitable to high drug concentration. Sterile injectable solutions can be prepared by incorporating the active compound (i.e., the ligand) in the required amount in an appropriate solvent with one or a combination of ingredients enumerated above, as required, followed by filtered sterilization. Generally, dispersions are prepared by incorporating the active compound into a sterile vehicle that contains a basic dispersion medium and the required other ingredients from those enumerated above. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum drying and freeze-drying that yields a powder of the active ingredient plus any additional desired ingredient from a previously sterile-filtered solution thereof. The proper fluidity of a solution can be maintained, for example, by the use of a coating such as lecithin, by the maintenance of the required particle size in the case of dispersion and by the use of surfactants. Prolonged absorption of injectable compositions can be brought about by including in the composition an agent that delays absorption, for example, monostearate salts and gelatin.

The anti-Tie1 protein ligands of the invention can be administered by a variety of methods known in the art, although for many applications, the preferred route/mode of administration is intravenous injection or infusion. For example, for therapeutic applications, the Tie1-binding ligand can be administered by intravenous infusion at a rate of less than 30, 20, 10, 5, or 1 mg/min to reach a dose of about 1 to 100 mg/m² or 7 to 25 mg/m². The route and/or mode of administration will vary depending upon the desired results. In certain embodiments, the active compound may be prepared with a carrier that will protect the compound against rapid release, such as a controlled release formulation, including implants, and microencapsulated delivery systems. Biodegradable, biocompatible polymers can be used, such as ethylene vinyl acetate, polyanhydrides, polyglycolic acid, collagen, polyorthoesters, and polylactic acid. Many methods for the preparation of such formulations are patented or generally known. See, e.g., Sustained and Controlled Release Drug Delivery Systems, J. R. Robinson, ed., Marcel Dekker, Inc., New York, 1978.

In certain embodiments, the ligand may be orally administered, for example, with an inert diluent or an assimilable edible carrier. The compound (and other ingredients, if desired) may also be enclosed in a hard or soft shell gelatin capsule, compressed into tablets, or incorporated directly into the subject's diet. For oral therapeutic administration, the compounds may be incorporated with excipients and used in the form of ingestible tablets, buccal tablets, troches, capsules, elixirs, suspensions, syrups, wafers, and the like. To administer a compound of the invention by other than parenteral administration, it may be necessary to coat the compound with, or co-administer the compound with, a material to prevent its inactivation.

Pharmaceutical compositions can be administered with medical devices known in the art. For example, in a preferred embodiment, a pharmaceutical composition of the invention can be administered with a needleless hypodermic injection device, such as the devices disclosed in U.S. Pat. Nos. 5,399,163, 5,383,851, 5,312,335, 5,064,413, 4,941,880, 4,790,824, or 4,596,556. Examples of well-known implants and modules useful in the invention include: U.S. Pat. No. 4,487,603, which discloses an implantable micro-infusion pump for dispensing medication at a controlled rate; U.S. Pat. No. 4,486,194, which discloses a therapeutic device for administering medicants through the skin; U.S. Pat. No. 4,447,233, which discloses a medication infusion pump for delivering medication at a precise infusion rate; U.S. Pat. No. 4,447,224, which discloses a variable flow implantable infusion apparatus for continuous drug delivery; U.S. Pat. No. 4,439,196, which discloses an osmotic drug delivery system having multi-chamber compartments; and U.S. Pat. No. 4,475,196, which discloses an osmotic drug delivery system. Of course, many other such implants, delivery systems, and modules are also known.

In certain embodiments, the compounds of the invention can be formulated to ensure proper distribution in vivo. For example, the blood-brain barrier (BBB) excludes many highly hydrophilic compounds. To ensure that the therapeutic compounds of the invention cross the BBB (if desired), they can be formulated, for example, in liposomes. For methods of manufacturing liposomes, see, e.g., U.S. Pat. Nos. 4,522,811; 5,374,548; and 5,399,331. The liposomes may include one or more moieties which are selectively transported into specific cells or organs, thus enhance targeted drug delivery (see, e.g., V. V. Ranade (1989) J. Clin. Pharmacol. 29:685).

Dosage regimens are adjusted to provide the optimum desired response (e.g., a therapeutic response). For example, a single bolus may be administered, several divided doses may be administered over time or the dose may be proportionally reduced or increased as indicated by the exigencies of the therapeutic situation. It is especially advantageous to formulate parenteral compositions in dosage unit form for ease of administration and uniformity of dosage. Dosage unit form as used herein refers to physically discrete units suited as unitary dosages for the subjects to be treated; each unit contains a predetermined quantity of active compound calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. The specification for the dosage unit forms of the invention are dictated by and directly dependent on (a) the unique characteristics of the active compound and the particular therapeutic effect to be achieved, and (b) the limitations inherent in the art of compounding such an active compound for the treatment of sensitivity in individuals.

An exemplary, non-limiting range for a therapeutically or prophylactically effective amount of an antibody of the invention is 0.1-20 mg/kg, more preferably 1-10 mg/kg. The Tie1-binding antibody can be administered by intravenous infusion at a rate of less than 30, 20, 10, 5, or 1 mg/min to reach a dose of about 1 to 100 mg/m² or about 5 to 30 mg/m². For ligands smaller in molecular weight than an antibody, appropriate amounts can be proportionally less. It is to be noted that dosage values may vary with the type and severity of the condition to be alleviated. It is to be further understood that for any particular subject, specific dosage regimens should be adjusted over time according to the individual need and the professional judgment of the person administering or supervising the administration of the compositions, and that dosage ranges set forth herein are exemplary only and are not intended to limit the scope or practice of the claimed composition.

The pharmaceutical compositions of the invention may include a “therapeutically effective amount” or a “prophylactically effective amount” of an Tie1-binding ligand of the invention. A “therapeutically effective amount” refers to an amount effective, at dosages and for periods of time necessary, to achieve the desired therapeutic result. A therapeutically effective amount of the composition may vary according to factors such as the disease state, age, sex, and weight of the individual, and the ability of the protein ligand to elicit a desired response in the individual. A therapeutically effective amount is also one in which any toxic or detrimental effects of the composition are outweighed by the therapeutically beneficial effects. A “therapeutically effective dosage” preferably inhibits a measurable parameter, e.g., inflammation or tumor growth rate by at least about 20%, more preferably by at least about 40%, even more preferably by at least about 60%, and still more preferably by at least about 80% relative to untreated subjects. The ability of a compound to inhibit a measurable parameter, e.g., cancer, can be evaluated in an animal model system predictive of efficacy in human tumors. Alternatively, this property of a composition can be evaluated by examining the ability of the compound to inhibit, such inhibition in vitro by assays known to the skilled practitioner.

A “prophylactically effective amount” refers to an amount effective, at dosages and for periods of time necessary, to achieve the desired prophylactic result. Typically, since a prophylactic dose is used in subjects prior to or at an earlier stage of disease, the prophylactically effective amount will be less than the therapeutically effective amount.

Also within the scope of the invention are kits including the protein ligand that binds to Tie1 and instructions for use, e.g., treatment, prophylactic, or diagnostic use. In one embodiment, the instructions for diagnostic applications include the use of the Tie1-binding ligand (e.g., antibody or antigen-binding fragment thereof, or other polypeptide or peptide) to detect Tie1, in vitro, e.g., in a sample, e.g., a biopsy or cells from a patient having an inflammatory disorder or a cancer or neoplastic disorder, or in vivo. In another embodiment, the instructions for therapeutic applications include suggested dosages and/or modes of administration in a patient with a cancer or neoplastic disorder. The kit can further contain a least one additional reagent, such as a diagnostic or therapeutic agent, e.g., a diagnostic or therapeutic agent as described herein, and/or one or more additional Tie1-binding ligands, formulated as appropriate, in one or more separate pharmaceutical preparations.

Stabilization and Retention

In one embodiment, an Tie1-binding ligand (e.g., a Tie1-binding antibody described herein) is physically associated with a moiety that improves its stabilization and/or retention in circulation, e.g., in blood, serum, lymph, or other tissues.

For example, an Tie1-binding ligand can be associated with a polymer, e.g., a substantially non-antigenic polymers, such as polyalkylene oxides or polyethylene oxides. Suitable polymers will vary substantially by weight. Polymers having molecular number average weights ranging from about 200 to about 35,000 are usually selected for the purposes of the present invention. Molecular weights of from about 1,000 to about 15,000 are preferred and 2,000 to about 12,500 are particularly preferred.

For example, an Tie1-binding ligand can be conjugated to a water soluble polymer, e.g., hydrophilic polyvinyl polymers, e.g. polyvinylalcohol and polyvinylpyrrolidone. A non-limiting list of such polymers include polyalkylene oxide homopolymers such as polyethylene glycol (PEG) or polypropylene glycols, polyoxyethylenated polyols, copolymers thereof and block copolymers thereof, provided that the water solubility of the block copolymers is maintained. Additional useful polymers include polyoxyalkylenes such as polyoxyethylene, polyoxypropylene, and block copolymers of polyoxyethylene and polyoxypropylene (Pluronics); polymethacrylates; carbomers; branched or unbranched polysaccharides which comprise the saccharide monomers D-mannose, D- and L-galactose, fucose, fructose, D-xylose, L-arabinose, D-glucuronic acid, sialic acid, D-galacturonic acid, D-mannuronic acid (e.g. polymannuronic acid, or alginic acid), D-glucosamine, D-galactosamine, D-glucose and neuraminic acid including homopolysaccharides and heteropolysaccharides such as lactose, amylopectin, starch, hydroxyethyl starch, amylose, dextrane sulfate, dextran, dextrins, glycogen, or the polysaccharide subunit of acid mucopolysaccharides, e.g. hyaluronic acid; polymers of sugar alcohols such as polysorbitol and polymannitol; heparin or heparon.

Other compounds can also be attached to the same polymer, e.g., a cytotoxin, a label, or another targeting agent, e.g., another Tie1-binding ligand or an unrelated ligand. Mono-activated, alkoxy-terminated polyalkylene oxides (PAO's), e.g., monomethoxy-terminated polyethylene glycols (mPEG's); C₁₋₄ alkyl-terminated polymers; and bis-activated polyethylene oxides (glycols) can be used for crosslinking. See, e.g., U.S. Pat. No. 5,951,974.

In its most common form poly(ethylene glycol), PEG, is a linear or branched polyether terminated with hydroxyl groups and having the general structure:

HO—(CH₂CH₂O)_(n)—CH₂CH₂—OH

PEG can be synthesized by anionic ring opening polymerization of ethylene oxide initiated by nucleophilic attack of a hydroxide ion on the epoxide ring. Particularly useful for polypeptide modification is monomethoxy PEG, mPEG, having the general structure:

CH₃O—(CH₂CH₂O)_(n)—CH₂CH₂—OH

For further description, see, e.g., Roberts et al. (2002) Advanced Drug Delivery Reviews 54:459-476.

In one embodiment, the polymer prior to cross-linking need not be, but preferably is, water soluble. Generally, after crosslinking, the product is water soluble, e.g., exhibits a water solubility of at least about 0.01 mg/ml, and more preferably at least about 0.1 mg/ml, and still more preferably at least about 1 mg/ml. In addition, the polymer should not be highly immunogenic in the conjugate form, nor should it possess viscosity that is incompatible with intravenous infusion or injection if the conjugate is intended to be administered by such routes.

In one embodiment, the polymer contains only a single group which is reactive. This helps to avoid cross-linking of protein molecules. However, it is within the scope herein to maximize reaction conditions to reduce cross-linking, or to purify the reaction products through gel filtration or ion exchange chromatography to recover substantially homogenous derivatives. In other embodiments, the polymer contains two or more reactive groups for the purpose of linking multiple ligands to the polymer backbone. Again, gel filtration or ion exchange chromatography can be used to recover the desired derivative in substantially homogeneous form.

The molecular weight of the polymer can range up to about 500,000 D, and preferably is at least about 20,000 D, or at least about 30,000 D, or at least about 40,000 D. The molecular weight chosen can depend upon the effective size of the conjugate to be achieved, the nature (e.g. structure, such as linear or branched) of the polymer, and the degree of derivatization.

The covalent crosslink can be used to attach an Tie1-binding ligand to a polymer, for example, crosslinking to the N-terminal amino group and epsilon amino groups found on lysine residues, as well as other amino, imino, carboxyl, sulfhydryl, hydroxyl or other hydrophilic groups. The polymer may be covalently bonded directly to the Tie1-binding ligand without the use of a multifunctional (ordinarily bifunctional) crosslinking agent. Covalent binding to amino groups is accomplished by known chemistries based upon cyanuric chloride, carbonyl diimidazole, aldehyde reactive groups (PEG alkoxide plus diethyl acetal of bromoacetaldehyde; PEG plus DMSO and acetic anhydride, or PEG chloride plus the phenoxide of 4-hydroxybenzaldehyde, activated succinimidyl esters, activated dithiocarbonate PEG, 2,4,5-trichlorophenylcloroformate or P-nitrophenylcloroformate activated PEG.) Carboxyl groups can be derivatized by coupling PEG-amine using carbodiimide. Sulfhydryl groups can be derivatized by coupling to maleimido-substituted PEG (e.g. alkoxy-PEG amine plus sulfosuccinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate) WO 97/10847 or PEG-maleimide commercially available from Shearwater Polymers, Inc., Huntsville, Ala.). Alternatively, free amino groups on the ligand (e.g. epsilon amino groups on lysine residues) can be thiolated with 2-imino-thiolane (Traut's reagent) and then coupled to maleimide-containing derivatives of PEG, e.g., as described in Pedley et al., Br. J. Cancer, 70: 1126-1130 (1994).

Functionalized PEG polymers that can be attached to an Tie1-binding ligand are available, e.g., from Shearwater Polymers, Inc. (Huntsville, Ala.). Such commercially available PEG derivatives include, e.g., amino-PEG, PEG amino acid esters, PEG-hydrazide, PEG-thiol, PEG-succinate, carboxymethylated PEG, PEG-propionic acid, PEG amino acids, PEG succinimidyl succinate, PEG succinimidyl propionate, succinimidyl ester of carboxymethylated PEG, succinimidyl carbonate of PEG, succinimidyl esters of amino acid PEGs, PEG-oxycarbonylimidazole, PEG-nitrophenyl carbonate, PEG tresylate, PEG-glycidyl ether, PEG-aldehyde, PEG vinylsulfone, PEG-maleimide, PEG-orthopyridyl-disulfide, heterofunctional PEGs, PEG vinyl derivatives, PEG silanes, and PEG phospholides. The reaction conditions for coupling these PEG derivatives may vary depending on the Tie1-binding ligand, the desired degree of PEGylation, and the PEG derivative utilized. Some factors involved in the choice of PEG derivatives include: the desired point of attachment (such as lysine or cysteine R-groups), hydrolytic stability and reactivity of the derivatives, stability, toxicity and antigenicity of the linkage, suitability for analysis, etc. Specific instructions for the use of any particular derivative are available from the manufacturer.

The conjugates of an Tie1-binding ligand and a polymer can be separated from the unreacted starting materials, e.g., by gel filtration or ion exchange chromatography, e.g., HPLC. Heterologous species of the conjugates are purified from one another in the same fashion. Resolution of different species (e.g. containing one or two PEG residues) is also possible due to the difference in the ionic properties of the unreacted amino acids. See, e.g., WO 96/34015.

Treatments

Protein ligands that bind to Tie1 (e.g., those described herein) have therapeutic and prophylactic utilities. For example, these ligands can be administered to cells in culture, e.g. in vitro or ex vivo, or in a subject, e.g., in vivo, to treat, prevent, and/or diagnose a variety of disorders, such as endothelial cell disorders, blood vessel development disorders, wound healing, inflammatory diseases and cancers, particularly metastatic cancers.

As used herein, the term “treat” or “treatment” is defined as the application or administration of an Tie1-binding antibody, alone or in combination with one or more other agents (e.g., a second agent) to a subject, e.g., a patient, or application or administration of the agent to an isolated tissue or cell, e.g., cell line, from a subject, e.g., a patient, who has a disorder (e.g., a disorder as described herein), a symptom of a disorder or a predisposition toward a disorder, with the purpose to cure, heal, alleviate, relieve, alter, remedy, ameliorate, improve or affect the disorder, the symptoms of the disorder or the predisposition toward the disorder. Treating a cell refers to the inhibition of growth or activity, ablation, killing of a cell in vitro or in vivo, or otherwise reducing capacity of a cell, e.g., an aberrant cell, to mediate a disorder, e.g., a disorder as described herein (e.g., a cancerous disorder).

In one embodiment, “treating a cell” refers to a reduction in the activity and/or proliferation of a cell, e.g., a hyperproliferative cell. Such reduction does not necessarily indicate a total elimination of the cell, but a reduction, e.g., a statistically significant reduction, in the activity or the number of the cell. An example of a reduction in activity is a reduction in migration of the cell or a reduction in cell differentiation.

As used herein, an amount of an Tie1-binding ligand effective to treat a disorder, or a “therapeutically effective amount” refers to an amount of the ligand which is effective, upon single or multiple dose administration to a subject, in treating a cell, e.g., an endothelial cell (e.g., a Tie1-expressing endothelial cell) or cancer cell (particularly a metastatic cell thereof), or in prolonging curing, alleviating, relieving or improving a subject with a disorder as described herein beyond that expected in the absence of such treatment. As used herein, “inhibiting the growth” of the neoplasm refers to slowing, interrupting, arresting or stopping its growth and metastases and does not necessarily indicate a total elimination of the neoplastic growth.

As used herein, an amount of an Tie1-binding ligand effective to prevent a disorder, or a “a prophylactically effective amount” of the ligand refers to an amount of an Tie1-binding ligand, e.g., an Tie1-binding antibody described herein, which is effective, upon single- or multiple-dose administration to the subject, in preventing or delaying the occurrence of the onset or recurrence of a disorder, e.g., an endothelial cell-related disorder, a blood vessel development disorder, an inflammatory disease or a cancer.

The terms “induce”, “inhibit”, “potentiate”, “elevate”, “increase”, “decrease” or the like, e.g., which denote quantitative differences between two states, refer to a difference, e.g., a statistically significant difference, between the two states. For example, “an amount effective to inhibit the proliferation of the Tie1-expressing hyperproliferative cells” means that the rate of growth of the cells will be different, e.g., statistically significantly different, from the untreated cells.

As used herein, the term “subject” is intended to include human and non-human animals. Preferred human animals include a human patient having a disorder characterized by abnormal cell proliferation or cell differentiation. The term “non-human animals” of the invention includes all vertebrates, e.g., non-mammals (such as chickens, amphibians, reptiles) and mammals, such as non-human primates, sheep, dog, cow, pig, etc.

In one embodiment, the subject is a human subject. Alternatively, the subject can be a mammal expressing a Tie1-like antigen with which an antibody of the invention cross-reacts. A protein ligand of the invention can be administered to a human subject for therapeutic purposes (discussed further below). Moreover, an Tie1-binding ligand can be administered to a non-human mammal expressing the Tie1-like antigen to which the ligand binds (e.g., a primate, pig or mouse) for veterinary purposes or as an animal model of human disease. Regarding the latter, such animal models may be useful for evaluating the therapeutic efficacy of the ligand (e.g., testing of dosages and time courses of administration).

In one embodiment, the invention provides a method of treating (e.g., inhibiting, ablating or killing) a cell (e.g., a non-cancerous cell, e.g., a normal, benign or hyperplastic cell, or a cancerous cell, e.g., a malignant cell, e.g., cell found in a solid tumor, a soft tissue tumor, or a metastatic lesion (e.g., a cell found in renal, urothelial, colonic, rectal, pulmonary, breast or hepatic, cancers and/or metastasis)). Methods of the invention include the steps of contacting the cell with an Tie1-binding ligand, e.g., an Tie1-binding antibody described herein, in an amount sufficient to treat, e.g., inhibit, ablate or kill, the cell.

The subject method can be used on cells in culture, e.g. in vitro or ex vivo. For example, cancerous or metastatic cells (e.g., renal, urothelial, colon, rectal, lung, breast, ovarian, prostatic, or liver cancerous or metastatic cells) can be cultured in vitro in culture medium, e.g., with endothelial cells, and the contacting step can be effected by adding the Tie1-binding ligand to the culture medium. The method can be performed on cells (e.g., cancerous or metastatic cells) present in a subject, as part of an in vivo (e.g., therapeutic or prophylactic) protocol. For in vivo embodiments, the contacting step is effected in a subject and includes administering the Tie1-binding ligand to the subject under conditions effective to permit both binding of the ligand to the cell and the treating, e.g., the killing or ablating of the cell.

The method can be used to treat a cancer. As used herein, the terms “cancer”, “hyperproliferative”, “malignant”, and “neoplastic” are used interchangeably, and refer to those cells an abnormal state or condition characterized by rapid proliferation or neoplasm. The terms include all types of cancerous growths or oncogenic processes, metastatic tissues or malignantly transformed cells, tissues, or organs, irrespective of histopathologic type or stage of invasiveness. “Pathologic hyperproliferative” cells occur in disease states characterized by malignant tumor growth.

The common medical meaning of the term “neoplasia” refers to “new cell growth” that results as a loss of responsiveness to normal growth controls, e.g. to neoplastic cell growth. A “hyperplasia” refers to cells undergoing an abnormally high rate of growth. However, as used herein, the terms neoplasia and hyperplasia can be used interchangeably, as their context will reveal, referring generally to cells experiencing abnormal cell growth rates. Neoplasias and hyperplasias include “tumors,” which may be benign, premalignant or malignant. In one embodiment, reduction in Tie1 activity by a Tie1-binding ligand can reduce or prevent angiogenesis near and around the tumor, thereby reducing or preventing tumor growth. In another embodiment, the neoplasia includes endothelial cells that are proliferating abnormally. A Tie1-binding ligand can be used to modulate the cells of the neoplasia themselves.

Examples of cancerous disorders include, but are not limited to, solid tumors, soft tissue tumors, and metastatic lesions. Examples of solid tumors include malignancies, e.g., sarcomas, adenocarcinomas, and carcinomas, of the various organ systems, such as those affecting lung, breast, lymphoid, gastrointestinal (e.g., colon), and genitourinary tract (e.g., renal, urothelial cells), pharynx, prostate, ovary as well as adenocarcinomas which include malignancies such as most colon cancers, rectal cancer, renal-cell carcinoma, liver cancer, non-small cell carcinoma of the lung, cancer of the small intestine and so forth. Metastatic lesions of the aforementioned cancers can also be treated or prevented using the methods and compositions of the invention.

The subject method can be useful in treating malignancies of the various organ systems, such as those affecting lung, breast, lymphoid, gastrointestinal (e.g., colon), and genitourinary tract, prostate, ovary, pharynx, as well as adenocarcinomas which include malignancies such as most colon cancers, renal-cell carcinoma, prostate cancer and/or testicular tumors, non-small cell carcinoma of the lung, cancer of the small intestine and cancer of the esophagus. Exemplary solid tumors that can be treated include: fibrosarcoma, myxosarcoma, liposarcoma, chondrosarcoma, osteogenic sarcoma, chordoma, angiosarcoma, endotheliosarcoma, lymphangiosarcoma, lymphangioendotheliosarcoma, synovioma, mesothelioma, Ewing's tumor, leiomyosarcoma, rhabdomyosarcoma, colon carcinoma, pancreatic cancer, breast cancer, ovarian cancer, prostate cancer, squamous cell carcinoma, basal cell carcinoma, adenocarcinoma, sweat gland carcinoma, sebaceous gland carcinoma, papillary carcinoma, papillary adenocarcinomas, cystadenocarcinoma, medullary carcinoma, bronchogenic carcinoma, renal cell carcinoma, hepatoma, bile duct carcinoma, choriocarcinoma, seminoma, embryonal carcinoma, Wilms' tumor, cervical cancer, testicular tumor, lung carcinoma, small cell lung carcinoma, non-small cell lung carcinoma, bladder carcinoma, epithelial carcinoma, glioma, astrocytoma, medulloblastoma, craniopharyngioma, ependymoma, pinealoma, hemangioblastoma, acoustic neuroma, oligodendroglioma, meningioma, melanoma, neuroblastoma, and retinoblastoma.

The term “carcinoma” is recognized by those skilled in the art and refers to malignancies of epithelial or endocrine tissues including respiratory system carcinomas, gastrointestinal system carcinomas, genitourinary system carcinomas, testicular carcinomas, breast carcinomas, prostatic carcinomas, endocrine system carcinomas, and melanomas. Exemplary carcinomas include those forming from tissue of the cervix, lung, prostate, breast, head and neck, colon and ovary. The term also includes carcinosarcomas, e.g., which include malignant tumors composed of carcinomatous and sarcomatous tissues. An “adenocarcinoma” refers to a carcinoma derived from glandular tissue or in which the tumor cells form recognizable glandular structures.

The term “sarcoma” is recognized by those skilled in the art and refers to malignant tumors of mesenchymal derivation.

The subject method can also be used to inhibit the proliferation of hyperplastic/neoplastic cells of hematopoietic origin, e.g., arising from myeloid, lymphoid or erythroid lineages, or precursor cells thereof. For instance, the invention contemplates the treatment of various myeloid disorders including, but not limited to, acute promyeloid leukemia (APML), acute myelogenous leukemia (AML) and chronic myelogenous leukemia (CML) (reviewed in Vaickus, L. (1991) Crit. Rev. in Oncol./Hemotol. 11:267-97). Lymphoid malignancies which may be treated by the subject method include, but are not limited to acute lymphoblastic leukemia (ALL), which includes B-lineage ALL and T-lineage ALL, chronic lymphocytic leukemia (CLL), prolymphocytic leukemia (PLL), hairy cell leukemia (HLL) and Waldenstrom's macroglobulinemia (WM). Additional forms of malignant lymphomas contemplated by the treatment method of the invention include, but are not limited to, non-Hodgkin's lymphoma and variants thereof, peripheral T-cell lymphomas, adult T-cell leukemia/lymphoma (ATL), cutaneous T-cell lymphoma (CTCL), large granular lymphocytic leukemia (LGF) and Hodgkin's disease. As Tie1 has been shown to be upregulated in acute myelogenous leukaemia and myelodysplastic syndrome (Verstovsek et al., 2001, Leuk, Lymphoma), B cell chronic lymphocytic leukaemia (Aguayo et al, 2001. Leukemia Research), ligands that interact with Tie1 can be used to detect, treat, or prevent these diseases.

Methods of administering Tie1-binding ligands are described in “Pharmaceutical Compositions”. Suitable dosages of the molecules used will depend on the age and weight of the subject and the particular drug used. The ligands can be used as competitive agents to inhibit, reduce an undesirable interaction, e.g., between a natural or pathological agent and the Tie1.

In one embodiment, the Tie1-binding ligands are used to inhibit (e.g., inhibit at least one activity of, reduce proliferation, migration, growth or viability) of a cell, e.g., an endothelial cell in vivo. The ligands can be used by themselves or conjugated to an agent, e.g., a cytotoxic drug, radioisotope. This method includes: administering the ligand alone or attached to a cytotoxic drug, to a subject requiring such treatment.

The terms “cytotoxic agent” and “cytostatic agent” and “anti-tumor agent” are used interchangeably herein and refer to agents that have the property of inhibiting the growth or proliferation (e.g., a cytostatic agent), or inducing the killing, of hyperproliferative cells, e.g., an aberrant cancer cell. In cancer therapeutic embodiment, the term “cytotoxic agent” is used interchangeably with the terms “anti-cancer” or “anti-tumor” to mean an agent, which inhibits the development or progression of a neoplasm, particularly a solid tumor, a soft tissue tumor, or a metastatic lesion.

Nonlimiting examples of anti-cancer agents include, e.g., anti-microtubule agents, topoisomerase inhibitors, antimetabolites, mitotic inhibitors, alkylating agents, intercalating agents, agents capable of interfering with a signal transduction pathway, agents that promote apoptosis, radiation, and antibodies against other tumor-associated antigens (including naked antibodies, immunotoxins and radioconjugates). Examples of the particular classes of anti-cancer agents are provided in detail as follows: antitubulin/antimicrotubule, e.g., paclitaxel, vincristine, vinblastine, vindesine, vinorelbin, taxotere; topoisomerase I inhibitors, e.g., topotecan, camptothecin, doxorubicin, etoposide, mitoxantrone, daunorubicin, idarubicin, teniposide, amsacrine, epirubicin, merbarone, piroxantrone hydrochloride; antimetabolites, e.g., 5-fluorouracil (5-FU), methotrexate, 6-mercaptopurine, 6-thioguanine, fludarabine phosphate, cytarabine/Ara-C, trimetrexate, gemcitabine, acivicin, alanosine, pyrazofurin, N-Phosphoracetyl-L-Asparate=PALA, pentostatin, 5-azacitidine, 5-Aza 2′-deoxycytidine, ara-A, cladribine, 5-fluorouridine, FUDR, tiazofurin, N-[5-[N-(3,4-dihydro-2-methyl-4-oxoquinazolin-6-ylmethyl)-N-methylamino]-2-thenoyl]-L-glutamic acid; alkylating agents, e.g., cisplatin, carboplatin, mitomycin C, BCNU=Carmustine, melphalan, thiotepa, busulfan, chlorambucil, plicamycin, dacarbazine, ifosfamide phosphate, cyclophosphamide, nitrogen mustard, uracil mustard, pipobroman, 4-ipomeanol; agents acting via other mechanisms of action, e.g., dihydrolenperone, spiromustine, and desipeptide; biological response modifiers, e.g., to enhance anti-tumor responses, such as interferon; apoptotic agents, such as actinomycin D; and anti-hormones, for example anti-estrogens such as tamoxifen or, for example antiandrogens such as 4′-cyano-3-(4-fluorophenylsulphonyl)-2-hydroxy-2-methyl-3′-(trifluoromethyl) propionanilide.

Since the Tie1-binding ligands recognize Tie1-expressing endothelial cells and can bind to endothelial cells that are associated with (e.g., in proximity of or intermingled with) cancer cells, e.g., cancerous lung, liver, colon, breast, ovarian, epidermal, laryngeal, and cartilage cells, and particularly metastatic cells thereof, Tie 1-binding ligands can be used to inhibit (e.g., inhibit at least one activity, reduce growth and proliferation, or kill) any such cells to which the ligands bind. Reducing endothelial cell activity near a cancer can indirectly inhibit (e.g., inhibit at least one activity, reduce growth and proliferation, or kill) the cancer cells which may be dependent on the endothelial cells for nutrients, growth signals and so forth.

Alternatively, the ligands bind to cells in the vicinity of the cancerous cells, but are sufficiently close to the cancerous cells to directly or indirectly inhibit (e.g., inhibit at least one activity, reduce growth and proliferation, or kill) the cancers cells. Thus, the Tie1-binding ligands (e.g., modified with a toxin, e.g., a cytotoxin) can be used to selectively inhibit (e.g., kill or ablate cells in cancerous tissue (including the cancerous cells themselves and endothelial cells associated with or invading the cancer).

The ligands may be used to deliver a variety of cytotoxic drugs including therapeutic drugs, a compound emitting radiation, molecules of plants, fungal, or bacterial origin, biological proteins, and mixtures thereof. The cytotoxic drugs can be intracellularly acting cytotoxic drugs, such as short-range radiation emitters, including, for example, short-range, high-energy α-emitters, as described herein.

Enzymatically active toxins and fragments thereof are exemplified by diphtheria toxin A fragment, non-binding active fragments of diphtheria toxin, exotoxin A (from Pseudomonas aeruginosa), ricin A chain, abrin A chain, modeccin A chain, α-sacrin, certain Aleurites fordii proteins, certain Dianthin proteins, Phytolacca americana proteins (PAP, PAPII and PAP-S), Morodica charantia inhibitor, curcin, crotin, Saponaria officinalis inhibitor, gelonin, mitogillin, restrictocin, phenomycin, and enomycin. Procedures for preparing enzymatically active polypeptides of the immunotoxins are described in WO84/03508 and WO85/03508, and in the appended Examples below. Examples of cytotoxic moieties that can be conjugated to the antibodies include adriamycin, chlorambucil, daunomycin, methotrexate, neocarzinostatin, and platinum.

In the case of polypeptide toxins, recombinant nucleic acid techniques can be used to construct a nucleic acid that encodes the ligand (or a protein component thereof) and the cytotoxin (or a protein component thereof) as translational fusions. The recombinant nucleic acid is then expressed, e.g., in cells and the encoded fusion polypeptide isolated.

Procedures for conjugating protein ligands (e.g., antibodies) with the cytotoxic agents have been previously described. Procedures for conjugating chlorambucil with antibodies are described by Flechner (1973) European Journal of Cancer, 9:741-745; Ghose et al. (1972) British Medical Journal, 3:495-499; and Szekerke, et al. (1972) Neoplasma, 19:211-215. Procedures for conjugating daunomycin and adriamycin to antibodies are described by Hurwitz, E. et al. (1975) Cancer Research, 35:1175-1181 and Arnon et al. (1982) Cancer Surveys, 1:429-449. Procedures for preparing antibody-ricin conjugates are described in U.S. Pat. No. 4,414,148 and by Osawa, T., et al. (1982) Cancer Surveys, 1:373-388 and the references cited therein. Coupling procedures as also described in EP 86309516.2.

To kill or ablate normal, benign hyperplastic, or cancerous cells, a first protein ligand is conjugated with a prodrug which is activated only when in close proximity with a prodrug activator. The prodrug activator is conjugated with a second protein ligand, preferably one which binds to a non-competing site on the target molecule. Whether two protein ligands bind to competing or non-competing binding sites can be determined by conventional competitive binding assays. Drug-prodrug pairs suitable for use in the practice of the invention are described in Blakely et al., (1996) Cancer Research, 56:3287-3292.

Alternatively, the Tie1-binding ligand can be coupled to high energy radiation emitters, for example, a radioisotope, such as ¹³¹I, a γ-emitter, which, when localized at the tumor site, results in a killing of several cell diameters. See, e.g., S. E. Order, “Analysis, Results, and Future Prospective of the Therapeutic Use of Radiolabeled Antibody in Cancer Therapy”, Monoclonal Antibodies for Cancer Detection and Therapy, R. W. Baldwin et al. (eds.), pp 303-316 (Academic Press 1985). Other suitable radioisotopes include α-emitters, such as ²¹²Bi, ²¹³Bi, and ²¹¹At, and β-emitters, such as ¹⁸⁶Re and ⁹⁰Y. Moreover, Lu¹¹⁷ may also be used as both an imaging and cytotoxic agent.

Radioimmunotherapy (RIT) using antibodies labeled with ¹³¹I, ⁹⁰Y, and ¹⁷⁷Lu is under intense clinical investigation. There are significant differences in the physical characteristics of these three nuclides and as a result, the choice of radionuclide is very critical in order to deliver maximum radiation dose to the tumor. The higher beta energy particles of ⁹⁰Y may be good for bulky tumors. The relatively low energy beta particles of ¹³¹I are ideal, but in vivo dehalogenation of radioiodinated molecules is a major disadvantage for internalizing antibody. In contrast, ¹⁷⁷Lu has low energy beta particle with only 0.2-0.3 mm range and delivers much lower radiation dose to bone marrow compared to ⁹⁰Y. In addition, due to longer physical half-life (compared to ⁹⁰Y), the tumor residence times are higher. As a result, higher activities (more mCi amounts) of ¹⁷⁷Lu labeled agents can be administered with comparatively less radiation dose to marrow. There have been several clinical studies investigating the use of ¹⁷⁷Lu labeled antibodies in the treatment of various cancers. (Mulligan T et al. (1995) Clin Cancer Res. 1:1447-1454; Meredith R F, et al. (1996) J Nucl Med 37:1491-1496; Alvarez R D, et al. (1997) Gynecologic Oncology 65: 94-101).

The Tie1-binding ligands can be used directly in vivo to eliminate antigen-expressing cells via natural complement-dependent cytotoxicity (CDC) or antibody-dependent cellular cytotoxicity (ADCC). The protein ligands of the invention, can include complement binding effector domain, such as the Fc portions from IgG1, -2, or -3 or corresponding portions of IgM which bind complement. In one embodiment, a population of target cells is ex vivo treated with a binding agent of the invention and appropriate effector cells. The treatment can be supplemented by the addition of complement or serum containing complement. Further, phagocytosis of target cells coated with a protein ligand of the invention can be improved by binding of complement proteins. In another embodiment target, cells coated with the protein ligand which includes a complement binding effector domain are lysed by complement.

Also encompassed by the invention is a method of killing or ablating which involves using the anti-Tie1 ligand for prophylaxis. For example, these materials can be used to prevent or delay development or progression of cancers.

Use of the therapeutic methods of the invention to treat cancers has a number of benefits. Since the protein ligands specifically recognize Tie1, other tissue is spared and high levels of the agent are delivered directly to the site where therapy is required. Treatment in accordance with the invention can be effectively monitored with clinical parameters. Alternatively, these parameters can be used to indicate when such treatment should be employed.

Tie1-binding ligands of the invention can be administered in combination with one or more of the existing modalities for treating cancers, including, but not limited to: surgery; radiation therapy, and chemotherapy.

Diagnostic Uses

Protein ligands that bind to Tie1 (e.g., antibodies, e.g., an antibody described herein) have in vitro and in vivo diagnostic, therapeutic and prophylactic utilities.

In one aspect, the invention provides a diagnostic method for detecting the presence of a Tie1, in vitro (e.g., a biological sample, such as tissue, biopsy, e.g., a cancerous tissue) or in vivo (e.g., in vivo imaging in a subject).

The method includes: (i) contacting a sample with Tie1-binding ligand; and (ii) detecting formation of a complex between the Tie1-binding ligand and the sample. The method can also include contacting a reference sample (e.g., a control sample) with the ligand, and determining the extent of formation of the complex between the ligand and the sample relative to the same for the reference sample. A change, e.g., a statistically significant change, in the formation of the complex in the sample or subject relative to the control sample or subject can be indicative of the presence of Tie1 in the sample.

Another method includes: (i) administering the Tie1-binding ligand to a subject; and (iii) detecting formation of a complex between the Tie1-binding ligand, and the subject. The detecting can include determining location or time of formation of the complex.

The Tie1-binding ligand can be directly or indirectly labeled with a detectable substance to facilitate detection of the bound or unbound antibody. Suitable detectable substances include various enzymes, prosthetic groups, fluorescent materials, luminescent materials and radioactive materials.

Complex formation between the Tie1-binding ligand and Tie1 can be detected by measuring or visualizing either the ligand bound to the Tie1 or unbound ligand. Conventional detection assays can be used, e.g., an enzyme-linked immunosorbent assays (ELISA), a radioimmunoassay (RIA) or tissue immunohistochemistry. Further to labeling the Tie1-binding ligand, the presence of Tie1 can be assayed in a sample by a competition immunoassay utilizing standards labeled with a detectable substance and an unlabeled Tie1-binding ligand. In one example of this assay, the biological sample, the labeled standards and the Tie1 binding agent are combined and the amount of labeled standard bound to the unlabeled ligand is determined. The amount of Tie1 in the sample is inversely proportional to the amount of labeled standard bound to the Tie1 binding agent.

Fluorophore and chromophore labeled protein ligands can be prepared. Since antibodies and other proteins absorb light having wavelengths up to about 310 nm, the fluorescent moieties should be selected to have substantial absorption at wavelengths above 310 nm and preferably above 400 nm. A variety of suitable fluorescers and chromophores are described by Stryer (1968) Science, 162:526 and Brand, L. et al. (1972) Annual Review of Biochemistry, 41:843-868. The protein ligands can be labeled with fluorescent chromophore groups by conventional procedures such as those disclosed in U.S. Pat. Nos. 3,940,475, 4,289,747, and 4,376,110. One group of fluorescers having a number of the desirable properties described above is the xanthene dyes, which include the fluoresceins and rhodamines. Another group of fluorescent compounds are the naphthylamines. Once labeled with a fluorophore or chromophore, the protein ligand can be used to detect the presence or localization of the Tie1 in a sample, e.g., using fluorescent microscopy (such as confocal or deconvolution microscopy).

Histological Analysis. Immunohistochemistry can be performed using the protein ligands described herein. For example, in the case of an antibody, the antibody can synthesized with a label (such as a purification or epitope tag), or can be detectably labeled, e.g., by conjugating a label or label-binding group. For example, a chelator can be attached to the antibody. The antibody is then contacted to a histological preparation, e.g., a fixed section of tissue that is on a microscope slide. After an incubation for binding, the preparation is washed to remove unbound antibody. The preparation is then analyzed, e.g., using microscopy, to identify if the antibody bound to the preparation. The method can be used to evaluate an endothelial cell or tissue formed by endothelial cells, e.g., blood vessels.

The antibody (or other polypeptide or peptide) can be unlabeled at the time of binding. After binding and washing, the antibody is labeled in order to render it detectable.

Protein Arrays. The Tie1-binding ligand can also be immobilized on a protein array. The protein array can be used as a diagnostic tool, e.g., to screen medical samples (such as isolated cells, blood, sera, biopsies, and the like). Of course, the protein array can also include other ligands, e.g., that bind to Tie1 or to other target molecules, such as hyaluronic acid.

Methods of producing polypeptide arrays are described, e.g., in De Wildt et al. (2000) Nat. Biotechnol. 18:989-994; Lueking et al. (1999) Anal. Biochem. 270:103-111; Ge (2000) Nucleic Acids Res. 28, e3, I-VII; MacBeath and Schreiber (2000) Science 289:1760-1763; WO 01/40803 and WO 99/51773A1. Polypeptides for the array can be spotted at high speed, e.g., using commercially available robotic apparati, e.g., from Genetic MicroSystems or BioRobotics. The array substrate can be, for example, nitrocellulose, plastic, glass, e.g., surface-modified glass. The array can also include a porous matrix, e.g., acrylamide, agarose, or another polymer.

For example, the array can be an array of antibodies, e.g., as described in De Wildt, supra. Cells that produce the protein ligands can be grown on a filter in an arrayed format. Polypeptide production is induced, and the expressed polypeptides are immobilized to the filter at the location of the cell.

A protein array can be contacted with a labeled target to determine the extent of binding of the target to each immobilized polypeptide from the diversity strand library. If the target is unlabeled, a sandwich method can be used, e.g., using a labeled probed, to detect binding of the unlabeled target.

Information about the extent of binding at each address of the array can be stored as a profile, e.g., in a computer database. The protein array can be produced in replicates and used to compare binding profiles, e.g., of a target and a non-target. Thus, protein arrays can be used to identify individual members of the diversity strand library that have desired binding properties with respect to one or more molecules.

FACS. (Fluorescent Activated Cell Sorting). The Tie1-binding ligand can be used to label cells, e.g., cells in a sample (e.g., a patient sample). The ligand is also attached (or attachable) to a fluorescent compound. The cells can then be sorted using fluorescent activated cell sorted (e.g., using a sorter available from Becton Dickinson Immunocytometry Systems, San Jose Calif.; see also U.S. Pat. Nos. 5,627,037; 5,030,002; and 5,137,809). As cells pass through the sorter, a laser beam excites the fluorescent compound while a detector counts cells that pass through and determines whether a fluorescent compound is attached to the cell by detecting fluorescence. The amount of label bound to each cell can be quantified and analyzed to characterize the sample.

The sorter can also deflect the cell and separate cells bound by the ligand from those cells not bound by the ligand. The separated cells can be cultured and/or characterized.

In vivo Imaging. In still another embodiment, the invention provides a method for detecting the presence of a Tie1-expressing cancerous tissues in vivo. The method includes (i) administering to a subject (e.g., a patient having a cancer or neoplastic disorder) an Tie1-binding antibody, conjugated to a detectable marker; (ii) exposing the subject to a means for detecting said detectable marker to the Tie1-expressing tissues or cells. For example, the method can be used visualize blood vessels or the location of endothelial cells, e.g., Tie1-expressing endothelial cells. The subject can be imaged, e.g., by NMR or other tomographic means.

Examples of labels useful for diagnostic imaging in accordance with the invention include radiolabels such as ¹³¹I, ¹¹¹In, ¹²³I, ^(99m)Tc, ³²P, ¹²⁵I, ³H, ¹⁴C, and ¹⁸⁸Rh, fluorescent labels such as fluorescein and rhodamine, nuclear magnetic resonance active labels, positron emitting isotopes detectable by a positron emission tomography (“PET”) scanner, chemiluminescers such as luciferin, and enzymatic markers such as peroxidase or phosphatase. Short-range radiation emitters, such as isotopes detectable by short-range detector probes can also be employed. The protein ligand can be labeled with such reagents using known techniques. For example, see Wensel and Meares (1983) Radioimmunoimaging and Radioimmunotherapy, Elsevier, New York for techniques relating to the radiolabeling of antibodies and D. Colcher et al. (1986) Meth. Enzymol. 121: 802-816.

A radiolabeled ligand of this invention can also be used for in vitro diagnostic tests. The specific activity of a isotopically-labeled ligand depends upon the half-life, the isotopic purity of the radioactive label, and how the label is incorporated into the antibody.

Procedures for labeling polypeptides with the radioactive isotopes (such as ¹⁴C, ³H, ³⁵S, ¹²⁵I, ³²P, ¹³¹I) are generally known. For example, tritium labeling procedures are described in U.S. Pat. No. 4,302,438. Iodinating, tritium labeling, and ³⁵S labeling procedures, e.g., as adapted for murine monoclonal antibodies, are described, e.g., by Goding, J. W. (Monoclonal antibodies: principles and practice: production and application of monoclonal antibodies in cell biology, biochemistry, and immunology 2nd ed. London; Orlando: Academic Press, 1986. pp 124-126) and the references cited therein. Other procedures for iodinating polypeptides, such as antibodies, are described by Hunter and Greenwood (1962) Nature 144:945, David et al. (1974) Biochemistry 13:1014-1021, and U.S. Pat. Nos. 3,867,517 and 4,376,110. Radiolabeling elements which are useful in imaging include ¹²³I, ¹³¹I, ¹¹¹In, and ^(99m)Tc, for example. Procedures for iodinating antibodies are described by Greenwood, F. et al. (1963) Biochem. J. 89:114-123; Marchalonis, J. (1969) Biochem. J. 113:299-305; and Morrison, M. et al. (1971) Immunochemistry 289-297. Procedures for ^(99m)Tc-labeling are described by Rhodes, B. et al. in Burchiel, S. et al. (eds.), Tumor Imaging: The Radioimmunochemical Detection of Cancer, New York: Masson 111-123 (1982) and the references cited therein. Procedures suitable for ¹¹¹In-labeling antibodies are described by Hnatowich, D. J. et al. (1983) J. Immul. Methods, 65:147-157, Hnatowich, D. et al. (1984) J. Applied Radiation, 35:554-557, and Buckley, R. G. et al. (1984) F.E.B.S. 166:202-204.

In the case of a radiolabeled ligand, the ligand is administered to the patient, is localized to the tumor bearing the antigen with which the ligand reacts, and is detected or “imaged” in vivo using known techniques such as radionuclear scanning using e.g., a gamma camera or emission tomography. See e.g., A. R. Bradwell et al., “Developments in Antibody Imaging”, Monoclonal Antibodies for Cancer Detection and Therapy, R. W. Baldwin et al., (eds.), pp 65-85 (Academic Press 1985). Alternatively, a positron emission transaxial tomography scanner, such as designated Pet VI located at Brookhaven National Laboratory, can be used where the radiolabel emits positrons (e.g., ¹¹C, ¹⁸F, ¹⁵O, and ¹³N).

MRI Contrast Agents. Magnetic Resonance Imaging (MRI) uses NMR to visualize internal features of living subject, and is useful for prognosis, diagnosis, treatment, and surgery. MRI can be used without radioactive tracer compounds for obvious benefit. Some MRI techniques are summarized in EP-A-0 502 814. Generally, the differences related to relaxation time constants T1 and T2 of water protons in different environments are used to generate an image. However, these differences can be insufficient to provide sharp high resolution images.

The differences in these relaxation time constants can be enhanced by contrast agents. Examples of such contrast agents include a number of magnetic agents paramagnetic agents (which primarily alter T1) and ferromagnetic or superparamagnetic (which primarily alter T2 response). Chelates (e.g., EDTA, DTPA and NTA chelates) can be used to attach (and reduce toxicity) of some paramagnetic substances (e.g., Fe⁺³ Mn⁺², Gd⁺³). Other agents can be in the form of particles, e.g., less than 10 μm to about 10 nM in diameter). Particles can have ferromagnetic, antiferromagnetic or superparamagnetic properties. Particles can include, e.g., magnetite (Fe₃O₄), γ-Fe₂O₃, ferrites, and other magnetic mineral compounds of transition elements. Magnetic particles may include: one or more magnetic crystals with and without nonmagnetic material. The nonmagnetic material can include synthetic or natural polymers (such as sepharose, dextran, dextrin, starch and the like

The Tie1-binding ligands can also be labeled with an indicating group containing of the NMR-active ¹⁹F atom, or a plurality of such atoms inasmuch as (i) substantially all of naturally abundant fluorine atoms are the ¹⁹F isotope and, thus, substantially all fluorine-containing compounds are NMR-active; (ii) many chemically active polyfluorinated compounds such as trifluoracetic anhydride are commercially available at relatively low cost, and (iii) many fluorinated compounds have been found medically acceptable for use in humans such as the perfluorinated polyethers utilized to carry oxygen as hemoglobin replacements. After permitting such time for incubation, a whole body MRI is carried out using an apparatus such as one of those described by Pykett (1982) Scientific American, 246:78-88 to locate and image cancerous tissues.

Information obtained from evaluating an Tie1-binding ligand, e.g., a ligand described herein, can be recorded on machine-compatible media, e.g., computer readable or computer accessible media. The information can be stored as a computer representation, e.g., in a database (e.g., in the case of imaging using a ligand, a database of images for one or a plurality of subjects). The term “computer representation” refers to information which is in a form that can be manipulated by a computer. The act of storing a computer representation refers to the act of placing the information in a form suitable for manipulation by a computer.

Also within the scope of the invention are kits including the protein ligand that binds to Tie1 and instructions for diagnostic use, e.g., the use of the Tie1-binding ligand (e.g., antibody or antigen-binding fragment thereof, or other polypeptide or peptide) to detect Tie1, in vitro, e.g., in a sample, e.g., a biopsy or cells from a patient having a cancer or neoplastic disorder, or in vivo, e.g., by imaging a subject. The kit can further contain a least one additional reagent, such as a label or additional diagnostic agent. For in vivo use the ligand can be formulated as a pharmaceutical composition.

The following invention is further illustrated by the following examples (commencing on the following page), which should not be construed as limiting.

EXAMPLES Example 1

An exemplary Tie1 amino acid sequence is as follows: (SEQ ID NO:2) MVWRVPPFLLPILFLASHVGAAVDLTLLANLRLTDPQRFFLTCVSGEAGAGRGSDAWGPPLLLEKDDRIV RTPPGPPLRLARNGSHQVTLRGFSKPSDLVGVFSCVGGAGARRTRVIYVHNSPGAHLLPDKVTHTVNKGD TAVLSARVHKEKQTDVIWKSNGSYFYTLDWHEAQDGRFLLQLPNVQPPSSGIYSATYLEASPLGSAFFRL IVRGCGAGRWGPGCTKECPGCLHGGVCHDHDGECVCPPGFTGTRCEQACREGRFGQSCQEQCPGISGCRG LTFCLPDPYGCSCGSGWRGSQCQEACAPGHFGADCRLQCQCQNGGTCDRFSGCVCPSGWHGVHCEKSDRI PQILNMASELEFNLETMPRINCAAAGNPFPVRGSIELRKPDGTVLLSTKAIVEPEKTTAEFEVPRLVLAD SGFWECRVSTSGGQDSRRFKVNVKVPPVPLAAPRLLTKQSRQLVVSPLVSFSGDSPISTVRLHYRPQDST MDWSTIVVDPSENVTLMNLRPKTGYSVRVQLSRPGEGGEGAWGPPTLMTTDCPEPLLQPWLEGWHVEGTD RLRVSWSLPLVPGPLVGDGFLLRLWDGTRSQERRENVSSPQARTALLTGLTPGTHYQLDVQLYHCTLLGP ASPPAHVLLPPSGPPAPRHLHAQALSDSEIQLTWKHPEALPGPISKYVVEVQVAGGAGDPLWIDVDRPEE TSTIIRGLNASTRYLFRMRASIQGLGDWSNTVEESTLGNGLQAEGPVQESRAAEEGLDQQLILAVVGSVS ATCLTILAALLTLVCIRRSCLHRRRTFTYQSGSGEETILQFSSGTLTLTRRPKLQPEPLSYPVLEWEDIT FEDLIGEGNFGQVIRAMIKKDGLKMNAAIKMLKEYASENDHRDFAGELEVLCKLGHHPNIINLLGACKNR GYLYIAIEYAPYGNLLDFLRKSRVLETDPAFAREHGTASTLSSRQLLRFASDAANGMQYLSEKQFIHRDL AARNVLVGENLASKIADFGLSRGEEVYVKKTMGRLPVRWMAIESLNYSVYTTKSDVWSFGVLLWEIVSLG GTPYCGMTCAELYEKLPQGYRMEQPRNCDDEVYELMRQCWRDRPYERPPFAQIALQLGRMLEARKAYVNM SLFENFTYAGIDATAEEA (SEQ ID NO:1) An exemplary nucleic acid sequence that encodes Tie1 is as follows: atggtctggc gggtgccccc tttcttgctc cccatcctct tcttggcttc tcatgtgggc   60 gcggcggtgg acctgacgct gctggccaac ctgcggctca cggaccccca gcgcttcttc  120 ctgacttgcg tgtctgggga ggccggggcg gggaggggct cggacgcctg gggcccgccc  180 ctgctgctgg agaaggacga ccgtatcgtg cgcaccccgc ccgggccacc cctgcgcctg  240 gcgcgcaacg gttcgcacca ggtcacgctt cgcggcttct ccaagccctc ggacctcgtg  300 ggcgtcttct cctgcgtggg cggtgctggg gcgcggcgca cgcgcgtcat ctacgtgcac  360 aacagccctg gagcccacct gcttccagac aaggtcacac acactgtgaa caaaggtgac  420 accgctgtac tttctgcacg tgtgcacaag gagaagcaga cagacgtgat ctggaagagc  480 aacggatcct acttctacac cctggactgg catgaagccc aggatgggcg gttcctgctg  540 cagctcccaa atgtgcagcc accatcgagc ggcatctaca gtgccactta cctggaagcc  600 agccccctgg gcagcgcctt ctttcggctc atcgtgcggg gttgtggggc tgggcgctgg  660 gggccaggct gtaccaagga gtgcccaggt tgcctacatg gaggtgtctg ccacgaccat  720 gacggcgaat gtgtatgccc ccctggcttc actggcaccc gctgtgaaca ggcctgcaga  780 gagggccgtt ttgggcagag ctgccaggag cagtgcccag gcatatcagg ctgccggggc  840 ctcaccttct gcctcccaga cccctatggc tgctcttgtg gatctggctg gagaggaagc  900 cagtgccaag aagcttgtgc ccctggtcat tttggggctg attgccgact ccagtgccag  960 tgtcagaatg gtggcacttg tgaccggttc agtggttgtg tctgcccctc tgggtggcat 1020 ggagtgcact gtgagaagtc agaccggatc ccccagatcc tcaacatggc ctcagaactg 1080 gagttcaact tagagacgat gccccggatc aactgtgcag ctgcagggaa ccccttcccc 1140 gtgcggggca gcatagagct acgcaagcca gacggcactg tgctcctgtc caccaaggcc 1200 attgtggagc cagagaagac cacagctgag ttcgaggtgc cccgcttggt tcttgcggac 1260 agtgggttct gggagtgccg tgtgtccaca tctggcggcc aagacagccg gcgcttcaag 1320 gtcaatgtga aagtgccccc cgtgcccctg gctgcacctc ggctcctgac caagcagagc 1380 cgccagcttg tggtctcccc gctggtctcg ttctctgggg atggacccat ctccactgtc 1440 cgcctgcact accggcccca ggacagtacc atggactggt cgaccattgt ggtggacccc 1500 agtgagaacg tgacgttaat gaacctgagg ccaaagacag gatacagtgt tcgtgtgcag 1560 ctgagccggc caggggaagg aggagagggg gcctgggggc ctcccaccct catgaccaca 1620 gactgtcctg agcctttgtt gcagccgtgg ttggagggct ggcatgtgga aggcactgac 1680 cggctgcgag tgagctggtc cttgcccttg gtgcccgggc cactggtggg cgacggtttc 1740 ctgctgcgcc tgtgggacgg gacacggggg caggagcggc gggagaacgt ctcatccccc 1800 caggcccgca ctgccctcct gacgggactc acgcctggca cccactacca gctggatgtg 1860 cagctctacc actgcaccct cctgggcccg gcctcgcccc ctgcacacgt gcttctgccc 1920 cccagtgggc ctccagcccc ccgacacctc cacgcccagg ccctctcaga ctccgagatc 1980 cagctgacat ggaagcaccc ggaggctctg cctgggccaa tatccaagta cgttgtggag 2040 gtgcaggtgg ctgggggtgc aggagaccca ctgtggatag acgtggacag gcctgaggag 2100 acaagcacca tcatccgtgg cctcaacgcc agcacgcgct acctcttccg catgcgggcc 2160 agcattcagg ggctcgggga ctggagcaac acagtagaag agtccaccct gggcaacggg 2220 ctgcaggctg agggcccagt ccaagagagc cgggcagctg aagagggcct ggatcagcag 2280 ctgatcctgg cggtggtggg ctccgtgtct gccacctgcc tcaccatcct ggccgccctt 2340 ttaaccctgg tgtgcatccg cagaagctgc ctgcatcgga gacgcacctt cacctaccag 2400 tcaggctcgg gcgaggagac catcctgcag ttcagctcag ggaccttgac acttacccgg 2460 cggccaaaac tgcagcccga gcccctgagc tacccagtgc tagagtggga ggacatcacc 2520 tttgaggacc tcatcgggga ggggaacttc ggccaggtca tccgggccat gatcaagaag 2580 gacgggctga agatgaacgc agccatcaaa atgctgaaag agtatgcctc tgaaaatgac 2640 catcgtgact ttgcgggaga actggaagtt ctgtgcaaat tggggcatca ccccaacatc 2700 atcaacctcc tgggggcctg taagaaccga ggttacttgt atatcgctat tgaatatgcc 2760 ccctacggga acctgctaga ttttctgcgg aaaagccggg tcctagagac tgacccagct 2820 tttgctcgag agcatgggac agcctctacc cttagctccc ggcagctgct gcgtttcgcc 2880 agtgatgcgg ccaatggcat gcagtacctg agtgagaagc agttcatcca cagggacctg 2940 gctgcccgga atgtgctggt cggagagaac ctagcctcca agattgcaga cttcggcctt 3000 tctcggggag aggaggttta tgtgaagaag acgatggggc gtctccctgt gcgctggatg 3060 gccattgagt ccctgaacta cagtgtctat accaccaaga gtgatgtctg gtcctttgga 3120 gtccttcttt gggagatagt gagccttgga ggtacaccct actgtggcat gacctgtgcc 3180 gagctctatg aaaagctgcc ccagggctac cgcatggagc agcctcgaaa ctgtgacgat 3240 gaagtgtacg agctgatgcg tcagtgctgg cgggaccgtc cctatgagcg accccccttt 3300 gcccagattg cgctacagct aggccgcatg ctggaagcca ggaaggccta tgtgaacatg 3360 tcgctgtttg agaacttcac ttacgcgggc attgatgcca cagctgagga ggcctga 3417

Example 2 Selection and Primary Screening

We have used phage display to select Tie1-specific antibodies from a very large phage library that displays immunoglobulins as Fab fragments. To isolate antibodies specific to Tie1, a phage displayed Fab antibody library was selected against the Tie1 extracellular domain fused to human Fc or to a histidine purification tag.

Selection in solution was done using biotin labelled antigen which was captured on streptavidin coated magnetic beads (M-280-DYNAL). Selection on cells expressing Tie1 was performed using a Kingfisher automated magnetic bead capture device. Selection on immobilized antigen was performed using Tie1-Fc coated onto immunotubes.

Several selection strategies were used:

Strategy 1: Round 1 (500 mM biotin labelled Tie1/magnetic beads), Round 2 (1×10⁷ Tie1 expressing cells/Kingfisher), Round 3 (1×10⁷ Tie1 expressing cells/Kingfisher)

Strategy 2: Round 1 (500 mM biotin labelled Tie1/magnetic beads), Round 2 (1×10⁷ Tie1 expressing cells/Kingfisher), (300 mM biotin labelled Tie1/magnetic beads)

Strategy 3: Round 1 (Tie1 Fc coated immunotubes at 5 μg/ml), Round 2 (Tie 1-Fc coated immunotubes), Round 3 (Tie1 Fc coated immunotubes plus depletion with human IgG)

Library members recovered from the selection strategies were tested for antigen binding in phage ELISA. Each isolate was tested for binding to coated Tie1 Fc. Strategy 1 did not identify any binding clones whereas strategy 2 identified 13 positive clones (n=95). Strategy 3 identified 86 binding clones (n=95).

Sequence analysis of the selected clones were grouped on the basis of the CDR3 selected of the heavy chain and resulted in 23 different antibodies with unique VH-CDR3 sequences.

We reformatted the selected Fabs as completely human antibodies by recloning the VH and VL coding sequences from the display library vector into two vectors of a mammalian expression vector system. These vectors contain the human kappa constant domain and the human gamma-1 heavy chain constant region. The vectors were co-transfected into mammalian CHO-K1 cells for expression and production of the corresponding complete IgGs. These antibodies were characterized using several assays as described below, including:

-   -   1. Western blotting and immunoprecipitation of Tie1 transfected         cells and primary human endothelial cells;     -   2. Immunofluorescence of Tie1 transfected cells and primary         human endothelial cells;     -   3. Stimulation and inhibition of Tie1 in Ba/F3 cells and primary         human endothelial cells; and     -   4. Immunostaining of human tissues.

We identified 23 antibodies that interact with Tie1. See also Table 1, below.

After sequence confirmation of the reformatted clones they were used in a transient transfection of Hek293T cells. After growth the IgG was purified from culture supernatants using a protein A column. The quality of purified IgG1 was determined using SDS-PAGE.

The specificity of the Tie1 specific IgG's can be determined in a whole cell ELISA on mouse lung microvascular endothelial cells (LEII) and LEII-Tie1 cells transfected with a Tie1 expression construct. Cells are seeded into 96 well plates at a density of 10,000 cells/well and were fixed using 4% paraformaldehyde. Staining and detection of binding of IgG1 to LE11 cells are detected using standard labelling with a HRP conjugated rabbit anti human HRP and TMB staining. Binding of purified IgG1 to LEII-Tie1 transfected cells can also be corrected for Tie1 protein that is expressed endogenously. Alternatively cells that have little or no endogenous Tie1 can be used for the analysis.

At least one of the binding antibodies—E3—functions as a Tie1 activating antibody in the BaF3 cell bioassay. We studied Tie1 phosphorylation in response to E3 IgG treatment in transiently transfected COS1 cells and human primary endothelial cells. Our results indicate that E3 IgG activates the Tie1 receptor. E3 can be used, instead of possible natural ligands to characterize several functions of Tie1 in vitro and in vivo. The region of Tie1 which interacts with E3 can be the target for small molecular weight compounds for Tie1 activation or inhibition. Although E3 functions in one particular Tie1 activating assay, E3 and other positives in this assay may also have inhibitory effect as to other functions or in other contexts. For example, E3 can inhibit tube formation by HUVEC cells. See below.

In addition, we found two antibodies that inhibit the survival effect conferred by E3 in the BaF3 cell bioassay. These two antibodies may inhibit dimerization of Tie1 induced by E3 in the BaF3 assay. Two antibodies, B2 and D11, completely blocked the viability of Tie1/EpoR cells when used in combination with E3. Thus, B2 and D11 antibodies can be used to inhibit Tie1 in vivo.

Methods Cell Culture

COS1 cells were cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetal calf serum (FCS), glutamine and antibiotics. The murine Ba/F3 pre-B lymphocytes were cultured in DMEM supplemented with 10% FCS, glutamine, antibiotics and 2 ng/ml interleukin-3 (Calbiochem). Human dermal microvascular endothelial cells (HDMVECs), obtained from PromoCell (Heidelberg, Germany) were cultured in endothelial cell medium provided by the supplier and used at passages 4-7.

Western Blotting and Immunoprecipitation

COS1 cells were transfected with pcDNA3-Tie1-V5 (1 μg DNA per 10 cm cell culture plate) using FUGENE 6 (Roche) according to manufacturer's instruction and incubated for 48 h before stimulation. For immunoprecipitation, Tie1 transfected cells and HMVEC cells were lysed in DOC-RIPA lysis buffer (50 mM Tris-HCl pH 8.0, 150 mM NaCl, 1% Triton-X-100, 0.1% SDS, 1% DOC, 10 mM EDTA) supplemented with aprotinin, leupeptin, PMSF and sodium vanadate. Immunoprecipitation was carried out from equal amount of cell lysates by incubating with polyclonal anti-human Tie1 antibodies (R&D), monoclonal anti-V5 antibodies (Invitrogen) or altogether 23 anti-Tie1 antibodies (1 μg/ml) for 1 to 2 h followed by incubation with protein G-Sepharose (Amersham Pharmacia Biotech AB) for 1 h. The immunoprecipitates were washed twice with PBS-T and twice with PBS, followed by elution with the Laemmli buffer and separation in 8% SDS-PAGE. The blots were probed with the 23 anti-Tie1 antibodies (5 μg/ml) and subsequently anti-human Fc antibodies conjugated with HRP.

Immunofluorescence Staining

COS1 cells on the glass coverslips were transiently transfected with pcDNA3-Tie1-V5 (the V5-epitope was added to the 3′ terminus of pcDNA3-Tie1) (1 μg DNA per 10 cm cell culture plate) using FUGENE™ 6 (Roche) according to manufacturer's instruction and incubated for 48 h before staining. Cells were fixed in 4% paraformaldehyde for 10 min at 4° C. If required, the cells were permeabilized with 0.2% Triton X-100 in PBS for 5 min. Unspecific binding sites were blocked by incubation with 1% BSA in PBS for 30 min. The cells were then stained with anti-Tie1 antibodies (5 μg/ml) and anti-V5 antibodies for 1 h at room temperature, followed by incubation with FITC-conjugated anti-human antibodies (DAKO, 40 μg/ml) and TRITC-conjugated anti-mouse antibodies (DAKO, 15 μg/ml) for 30 min. Hoechst 33258 fluorochrome (Sigma, 0.5 μg/ml) was used for the staining of the nuclei.

Ba/F3 Bioassay

To generate Tie1-EpoR expressing Ba/F3 cells for the bioassay, Ba/F3 pre-B cells were stably transfected with a nucleic acid that expresses chimeric receptor containing the extracellular domain of human Tie1 fused with the transmembrane and cytoplasmic domains of the mouse erythropoietin receptor. The nucleic acid used was a Tie1-EpoR chimeric cDNA in a pEF-BOS expression vector. The nucleic acid encoding the chimeric receptor was constructed by cloning the PCR amplified extracellular part of human Tie1 (bp 37-2316 of X60975) as EcoRI-BglII fragment into mEpoR-pcDNA vector. The cDNA encoding for the chimeric receptor consisting of the extracellular part of Tie1 fused with the transmembrane and intracellular domains of EpoR was subcloned into the pEF-BOS expression vector. Vector was linearized and co-transfected into Ba/F3 cells with pcDNA3.1(+) Zeo vector (Invitrogen). Stable cell pools were generated by selection with 250 μg/ml Zeocin. The expression of Tie1/EpoR fusion protein in several clones was analyzed by Western blotting with an antibody against EpoR.

To perform the assays, Ba/F3 cells expressing the Tie1-EpoR chimera were split in 96-well microtiter plates at 50 000 cells/well in the presence of the indicated concentrations of anti-Tie1 antibodies. As controls, Zeocin resistant pools not expressing the Tie1-EpoR were used. After 48 h, the viability of the cells was determined by adding MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (Sigma), 0.5 mg/ml), followed by further 2 h of culture, addition of an equal volume of cell lysis solution (10% SDS, 10 mM HCl) and incubation overnight at 37° C. Absorbance was measured at 540 nm.

Tie1 Phosphorylation Assay

COS1 cells were transfected with pcDNA3-Tie1-V5. After 24 h of transfection, the cells were serum starved for 8 h and then treated with E3 IgG. For the Tie1 phosphorylation assay, HDMVECs were cultured on 10 cm dishes to near confluence, starved (8-16 h) in serum free medium and stimulated as indicated. After the stimulations, the cells were lysed in lysis buffer (RIPA-DOC: 50 mM Tris-HCl pH 8.0, 150 mM NaCl, 1% Triton-X-100, 0.1% SDS, 0.5% DOC, 10 mM EDTA, supplemented with aprotinin, leupeptin, PMSF and sodium vanadate). Clarified lysates from transfected COS1 cells or HDMVECs were immunoprecipitated with anti-V5 or anti-Tie1 B9, respectively. Proteins were separated by SDS-PAGE, transferred to nitrocellulose and immunoblotted using the anti-phosphotyrosine and anti-Tie1 (R&D systems) antibodies.

Immunostaining of Human Tissues

To evaluate reactivity of anti-Tie1 antibodies in immunohistochemistry, 5 μm cyrosections of human kidney and lung were dried at room temperature for 30 min and fixed with cold acetone for 10 min. Slides were washed with PBS and treated with 0.03% H₂0₂ in PBS for 15 min to reduce endogenous peroxidase activity. TNB (30 min at room temperature) was used to block non-specific binding and sections were incubated with Tie1 antibodies at concentration of 10 μg/ml overnight at +4° C. After several washings with PBS, biotinylated anti human antibody (1:300, Zymed) was added to the tissues. Signal was amplified by using a TSA kit and detected with AEC staining.

Results

Western blotting, immunoprecipitation and immunofluorescence of Tie1 transfected cells and primary human endothelial cells (see Table 1).

TABLE 1 Assay Summary WB: Tie1- WB: IP: Tie1- IP: IF: Tie1- IF: BaF3 Clone transfected HDMEC transfected HDMEC transfected HDMEC assay E3 + + ND − + + + G2 + + ++ + + ++ − A2 + + ++ + + ++ − A10 + + ++ + + + − B2 + + + − + + − B9 + + ++ ++ ++ + − C2 + + ++ ++ + ++ − C7 + + ++ + + + − C10 + + ++ ++ ++ + − D11 + + + − + ++ − E11 + + ++ + + ++ − G10 + + ++ + ++ + − H1 + + ++ + ++ + − H4 + + ++ + + + − P-A1 + + ++ ++ + ++ − P-A10 + + ++ − + + − P-B1 + + + − weak + − P-B3 + + − − + + − P-C6 + + + − + ++ − P-D12 + + + − + + − P-F3 + + − − ++ ++ − P-F4 + + ++ − cross ++ − P-G3 + + ++ + + + − PH1 − − − − − − −

To confirm the binding ability of the 23 selected anti-Tie1 antibodies, we first performed western blotting and immunoprecipitation using COS1 cells transfected with pcDNA3-Tie1-V5 (V5 tagged) and primary endothelial cells. Next, to find out if the anti-Tie1 antibodies recognize Tie1 in living cells, those cells were studied by immunofluorescence staining. All the antibodies analyzed recognized both transfected and endogenous Tie1, although differences were detected in the binding affinity as shown in Table 1.

Stimulation and Inhibition of Tie1 in Tie1-EpoR Transfected Ba/F3 Cells and Human Primary Endothelial Cells

Although no ligand for Tie1 has been identified, we used the following efficient screening method for Tie1-binding ligands. Interleukin-3 dependent pre-B-lymphocyte (Ba/F3) cells were transfected with a construct that expresses a Tie1-EpoR fusion protein. Since Ba/F3 cells are IL-3 dependent, they die unless IL-3 is provided. However, Tie-EpoR receptor expressing Ba/F3 cells can survive and proliferate if the medium contains a Tie1-binding ligand, either a natural ligand or an artificial mimetic. Cell survival can be quantitated, e.g., by colorimetric MTT-assay, which measures mitochondrial activity.

The results from the BaF3 cell assays indicated that, of the 23 different monoclonal antibodies tested, only E3 IgG was able to promote survival of Tie1-EpoR cells whereas the viability of EpoR Ba/F3 cells used as a control was not affected by E3 IgG. The IgG part of the immunoglobulin molecule was needed for the survival effect of E3 IgG, as the E3 Fab fragment had no effect on the viability of Tie1-EpoR cells. A concentration of 50 ng/ml of E3 IgG gave almost maximal viability in Tie1-EpoR cell survival assays.

To test if the E3 IgG binding to the extracellular region of Tie1 induces autophosphorylation of Tie1, the Tie1 receptor phosphorylation level in response to E3 IgG treatment was studied in transiently transfected COS1 cells and human primary endothelial cells. COS1 cells were transfected with an expression vector containing a V5-tagged full length Tie1 cDNA, and, after serum starvation, the cells were treated with E3 IgG (200 ng/ml). Cell lysates were extracted at several time points and Tie1 was immunoprecipitated with anti-V5 followed by western blotting using anti-phosphotyrosine and anti-Tie1 antibodies. The results indicated that Tie1 is tyrosine phosphorylated after 10 to 30 min of E3 IgG stimulation. To determine if E3 IgG induces Tie1 phosphorylation in primary endothelial cells, HDMVEC cells were serum starved and stimulated with several concentrations of E3 for 60 min. Tie1 was then immunoprecipitated from cell lysates and subjected to anti-phosphotyrosine blotting analysis, which showed receptor phosphorylation following E3 IgG stimulation at 50-200 ng/ml. Also higher concentrations of E3 (500-1000 ng/ml) induced Tie1 phosphorylation but the response was more rapid and was most prominent after 5 min of stimulation.

To study the kinetics of E3 IgG induced Tie1 activation, cells were stimulated with E3 IgG (200 ng/ml) and receptor phosphorylation was studied at various time points. Tie1 phosphorylation was highest 15-30 min after E3 IgG treatment but phosphorylation persisted for up to 1 h.

To determine if any of the other monoclonal antibodies tested inhibit the survival effect of E3 IgG in Tie1-EpoR Ba/F3 assay, antibodies were studied in combination with E3 IgG. A concentration of 100 ng/ml of E3 IgG together with 100 (1:1) or 500 (1:5) ng/ml of the other antibodies were used and the viability of Tie1-EpoR cells was measured. The results from both combinations of E3 IgG and the test antibody (in 1:1 and 1:5 ratios) were similar and indicated that two of the 23 antibodies (B2 and D11) blocked completely the survival effect of E3 IgG (Table 2). Several antibodies (A2, A10, P-B1, P-B3 and P-C6) inhibited the viability effect of E3 IgG to some extent and two of the antibodies (G2 and C7) promoted the survival of Tie1/EpoR Ba/F3 cells in combination with E3 IgG.

TABLE 2 BaF3 Assay Average MTT activity Treatment in BaF3 cell assay St. Dev. IL3, 2 0.48 0.038 0 0.01 0.003 E3 0.61 0.032 E3 + G2 0.74 0.034 E3 + A2 0.38 0.016 E3 + A10 0.52 0.011 E3 + B2 0.00 0.001 E3 + B9 0.65 0.011 E3 + C2 0.62 0.016 E3 + C7 0.84 0.086 E3 + C10 0.67 0.004 E3 + D11 0.01 0.003 E3 + E11 0.61 0.048 E3 + G10 0.65 0.010 E3 + H1 0.60 0.017 E3 + H4 0.65 0.026 E3 + PA1 0.60 0.035 E3 + PA10 0.65 0.041 E3 + PB1 0.47 0.011 E3 + P-B3 0.51 0.007 E3 + PC6 0.35 0.008 E3 + PD12 0.60 0.038 E3 + PF3 0.55 0.032 E3 + PF4 0.56 0.009 E3 + PG3 0.77 0.030 E3 + PH1 0.63 0.040

Immunostaining of Human Tissues

The anti-Tie1 antibodies react with human Tie1 in cultured cells. It is also possible to determine whether they could stain human tissue samples from lung and kidney as well as from tumors by using biotinylated anti-Tie1 antibodies and detecting bound antibodies using labeled streptavidin or avidin.

In one embodiment, Tie ligands (such as the Tie1 antibodies described herein can be produced from gene-based vectors, such as transgenes or via adenoviral delivery.

Example 3 Exemplary Sequences

The following are sequences of exemplary immunoglobulin variable domains:

Translation of Reverse_Complement_VH-PA1-Tie1-phagemid.TXT(1-396) Universal code Total amino acid number: 132, MW = 14169 Max ORF: 1-396, 132 AA, MW = 14169   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ  ID  NO:3)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ  ID  NO:4)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTATTTACAAGATGTCTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  I  Y  K  M  S  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTTCTATCTATCCTTCTGGTGGCCAGACTAAGTAT  41  P  G  K  G  L  E  W  V  S  S  I  Y  P  S  G  G  Q  T  K  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGTCAAT  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  N 301 TACTATGATAGTAGTGGTTACGGTCCTATAGCTCCTGGACTTGACTACTGGGGCCAGGGA 101  Y  Y  D  S  S  G  Y  G  P  I  A  P  G  L  D  Y  W  G  Q  G 361 ACCCTGGTCACCGTCTCAAGCGCCTCCACCAAGGGC 121  T  L  V  T  V  S  S  A  S  T  K  G Translation of VL-PA1-Tie1-phagemid.TXT (1-311) Universal code Total amino acid number: 103, MW = 11169 Max ORF: 1-309, 103 AA, MW = 11169   1 CAAGACATCCAGATGACCCAGTCTCCAGGCACCCTGTCTTTGTCTCCAGGGGAAAGAGCC (SEQ ID NO:5)   1  Q  D  I  Q  M  T  Q  S  P  G  T  L  S  L  S  P  G  E  R  A (SEQ ID NO:6)  61 ACCCTCTCCTGCAGGGCCAGTCAGAGTGTTAGCAGCAGCTACTTAGCCTGGTACCAGCAG  21  T  L  S  C  R  A  S  Q  S  V  S  S  S  Y  L  A  W  Y  Q  Q 121 AAACCTGGCCAGGCTCCCAGGCTCCTCATCTATGGTGCATCCAGCAGGGCCACTGGCATC  41  K  P  G  Q  A  P  R  L  L  I  Y  G  A  S  S  R  A  T  G  I 181 CCAGACAGGTTCAGTGGCAGTGGGTCTGGGACAGACTTCACTCTCACCATCAGCAGACTG  61  P  D  R  F  S  G  S  G  S  G  T  D  F  T  L  T  I  S  R  L 241 GAGCCTGAAGATTTTGCAGTGTATTACTGTCAGCAGTATGGTAGCTCCCGGTGGACGTTC  81  E  P  E  D  F  A  V  Y  Y  C  Q  Q  Y  G  S  S  R  W  T  F 301 GGCCAAGGGAC 101  G  Q  G Translation of Reverse_Complement_VH-PA5-Tie1-phagemid.TXT (1-396) Universal code Total amino acid number: 132, MW = 14309 Max ORF: 1-396, 132 AA, MW = 14309   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:7)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:8)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTTATTACCTTATGTATTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  Y  Y  L  M  Y  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTTCTATCTATCCTTCTGGTGGCTGGACTGTTTAT  41  P  G  K  G  L  E  W  V  S  S  I  Y  P  S  G  G  W  T  V  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGTCAAT  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  N 301 TACTATGATAGTAGTGGTTACGGTCCTATAGCTCCTGGACTTGACTACTGGGGCCAGGGA 101  Y  Y  D  S  S  G  Y  G  P  I  A  P  G  L  D  Y  W  G  Q  G 361 ACCCTGGTCACCGTCTCAAGCGCCTCCACCAAGGGC 121  T  L  V  T  V  S  S  A  S  T  K  G Translation of VL-PA5-Tie1-phagemid.TXT (1-308) Universal code Total amino acid number: 101, MW = 10801 Max ORF: 85-306, 74 AA, MW = 7983   1 CAAGACATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTCGGAGACAGAGTC (SEQ ID NO:9)   1  Q  D  I  Q  M  T  Q  S  P  S  S  L  S  A  S  V  G  D  R  V (SEQ ID NO:10)  61 ACCATCACTTGCCGGGCAAGTTAGAGCATTAGCACCTCTTTAAATTGGTATCAGCAAAAA  21  T  I  T  C  R  A  S  *  S  I  S  T  S  L  N  W  Y  Q  Q  K 121 TCAGGGAAAGCCCCTAAGCTCCTGATATATGCTGCATCCAGTTTGCAAAGTGAAGTCCCA  41  S  G  K  A  P  K  L  L  I  Y  A  A  S  S  L  Q  S  E  V  P 181 TCAAGGTTCAGTGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCACCAGTCTGCAA  61  S  R  F  S  G  S  G  S  G  T  D  F  T  L  T  I  T  S  L  Q 241 CCTGAAGATTTTGCAACTTACTACTGTCAACAGAGTTACAGTACCCCTCCGACTTTCGGC  81  P  E  D  F  A  T  Y  Y  C  Q  Q  S  Y  S  T  P  P  T  F  G 301 CAAGGGAC 101  Q  G Translation of VH-PA6-Tie1-phagemid.TXT (1-439) Universal code Total amino acid number: 146, MW = 15647 Max ORF: 1-438, 146 AA, MW = 15647   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:11)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:12)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTATGTACGTTATGAAGTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  M  Y  V  M  K  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTTCTATCTATCCTTCTGGTGGCTATACTCGTTAT  41  P  G  K  G  L  E  W  V  S  S  I  Y  P  S  G  G  Y  T  R  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGTCAAT  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  N 301 TACTATGATAGTAGTGGTTACGGTCCTATAGCTCCTGGACTTGACTACTGGGGCCAGGGA 101  Y  Y  D  S  S  G  Y  G  P  I  A  P  G  L  D  Y  W  G  Q  G 361 ACCCTGGTCACCGTCTCAAGCGCCTCCACCAAGGGCCCATCGGTCTTCCCGCTAGCACCC 121  T  L  V  T  V  S  S  A  S  T  K  G  P  S  V  F  P  L  A  P 421 TCCTCCAAGAGCACCTCTG 141  S  S  K  S  T  S Translation of VL-PA6-Tie1-phagemid.TXT (1-311) Universal code Total amino acid number: 103, MW = 11056 Max ORF: 1-309, 103 AA, MW = 11056   1 CAAGACATCCAGATGACCCAGTCTCCAGGCACCCTGTCTTTGTCTCCAGGGGAAAGAGCC (SEQ ID NO:13)   1  Q  D  I  Q  M  T  Q  S  P  G  T  L  S  L  S  P  G  E  R  A (SEQ ID NO:14)  61 ACCCTCTCCTGCAGGGCCAGTCAGAGTGTTAGCAGCAGCTACTTAGCCTGGTACCAGCAG  21  T  L  S  C  R  A  S  Q  S  V  S  S  S  Y  L  A  W  Y  Q  Q 121 AAACCTGGCCAGGCTCCCAGGCTCCTCATCTATGGTGCATCCAGCAGGGCCACTGGCATC  41  K  P  G  Q  A  P  R  L  L  I  Y  G  A  S  S  R  A  T  G  I 181 CCAGACAGGTTCAGTGGCAGTGGGTCTGGGACAGACTTCACTCTCACCATCAGCAGACTG  61  P  D  R  F  S  G  S  G  S  G  T  D  F  T  L  T  I  S  R  L 241 GAGCCTGAAGATTTTGCAGTGTATTACTGTCAGCAGTATGGTAGCTCCCTATTCACTTTC  81  E  P  E  D  F  A  V  Y  Y  C  Q  Q  Y  G  S  S  L  F  T  F 301 GGCCCTGGGAC 101  G  P  G Translation of VH-PA10-Tie1-phagemid.TXT (1-439) Universal code Total amino acid number: 146, MW = 15499 Max ORF: 1-438, 146 AA, MW = 15499   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:15)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:16)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTTCTTACAAGATGGGTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  S  Y  K  M  G  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTTGGATCTATCCTTCTGGTGGCGGTACTACTTAT  41  P  G  K  G  L  E  W  V  S  W  I  Y  P  S  G  G  G  T  T  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGTCAAT  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  N 301 TACTATGATAGTAGTGGTTACGGTCCTATAGCTCCTGGACTTGACTACTGGGGCCAGGGA 101  Y  Y  D  S  S  G  Y  G  P  I  A  P  G  L  D  Y  W  G  Q  G 361 ACCCTGGTCACCGTCTCAAGCGCCTCCACCAAGGGCCCATCGGTCTTCCCGCTAGCACCC 121  T  L  V  T  V  S  S  A  S  T  K  G  P  S  V  F  P  L  A  P 421 TCCTCCAAGAGCACCTCTG 141  S  S  K  S  T  S Translation of VL-PA10-Tie1-phagemid.TXT (1-311) Universal code Total amino acid number: 103, MW = 11110 Max ORF: 1-309, 103 AA, MW = 11110   1 CAAGACATCCAGATGACCCAGTCTCCAGGCACCCTGTCTTTGTCTCCAGGGGAAAGAGCC (SEQ ID NO:17)   1  Q  D  I  Q  M  T  Q  S  P  G  T  L  S  L  S  P  G  E  R  A (SEQ ID NO:18)  61 ACCCTCTCCTGCAGGGCCAGTCAGAGTGTTAGCAGCAGCTACTTAGCCTGGTACCAGCAG  21  T  L  S  C  R  A  S  Q  S  V  S  S  S  Y  L  A  W  Y  Q  Q 121 AAACCTGGCCAGGCTCCCAGGCTCCTCATCTATGGTGCATCCAGCAGGGCCACTGGCATC  41  K  P  G  Q  A  P  R  L  L  I  Y  G  A  S  S  R  A  T  G  I 181 CCAGACAGGTTCAGTGGCAGTGGGTCTGGGACAGACTTCACTCTCACCATCAGCAGACTG  61  P  D  R  F  S  G  S  G  S  G  T  D  F  T  L  T  I  S  R  L 241 GAGCCTGAAGATTTTGCAGTGTATTACTGTCAGCAGTATGGTAGCTCACCGTGGACGTTC  81  E  P  E  D  F  A  V  Y  Y  C  Q  Q  Y  G  S  S  P  W  T  F 301 GGCCAAGGGAC 101  G  Q  G Translation of VH-PB1-Tie1-phagemid.TXT (1-446) Universal code Total amino acid number: 148, MW = 15809 Max ORF: 1-444, 148 AA, MW = 15809   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:19)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:20)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTCGTTACCCTATGGTTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  R  Y  P  M  V  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGTTATCTCTCCTTCTGGTGGCCAGACTTTTTAT  41  P  G  K  G  L  E  W  V  S  V  I  S  P  S  G  G  Q  T  F  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGGGGTC  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  G  V 301 CTCACCACCGCTTTTGATATCTGGGGCCAAGGGACAATGGTCACCGTCTCAAGCGCCTCC 101  L  T  T  A  F  D  I  W  G  Q  G  T  M  V  T  V  S  S  A  S 361 ACCAAGGGCCCATCGGTCTTCCCGCTAGCACCCTCCTCCAAAGCACCTCTGGGGGCACAG 121  T  K  G  P  S  V  F  P  L  A  P  S  S  K  A  P  L  G  A  Q 421 CGGCCCTGGGCTGCCTGGTCAAGGAC 141  R  P  W  A  A  W  S  R Translation of VL-PB1-Tie1-phagemid.TXT (1-308) Universal code Total amino acid number: 102, MW = 11057 Max ORF: 1-306, 102 AA, MW = 11057   1 CAAGACATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTGGGAGACAGAGTC (SEQ ID NO:21)   1  Q  D  I  Q  M  T  Q  S  P  S  S  L  S  A  S  V  G  D  R  V (SEQ ID NO:22)  61 ACCATCACTTGCCGGGCAAGTCAGAACATTAACAGCTATTTAAATTGGTATCAGCAGAAA  21  T  I  T  C  R  A  S  Q  N  I  N  S  Y  L  N  W  Y  Q  Q  K 121 CCAGGGCAAGCCCCTAAACTCCTGATCTATGCTGCCTCCAATTTGGAAACTGCGGTCCCA  41  P  G  Q  A  P  K  L  L  I  Y  A  A  S  N  L  E  T  A  V  P 181 TCAAGGTTCAGCGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGTAGCCTGCAG  61  S  R  F  S  G  S  G  S  G  T  D  F  T  L  T  I  S  S  L  Q 241 CCTGAAGATTTTGCAACTTATTATTGTCAACAATTTAATACTTACCCTCTCACTTTCGGC  81  P  E  D  F  A  T  Y  Y  C  Q  Q  F  N  T  Y  P  L  T  F  G 301 GGAGGGAC 101  G  G Translation of VH-PB3-Tie1-phagemid.TXT (1-393) Universal code Total amino acid number: 131, MW = 13931 Max ORF: 1-393, 131 AA, MW = 13931   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:23)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:24)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTCGTTACGGTATGCATTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  R  Y  G  M  H  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGTTATCTCTCCTTCTGGTGGCATGACTTATTAT  41  P  G  K  G  L  E  W  V  S  V  I  S  P  S  G  G  M  T  Y  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACACTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  T  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGTGGGA  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  G 301 GCTACCGGGCCTTTTGATATCTGGGGCCAAGGGACAATGGTCACCGTCTCAAGCGCCTCC 101  A  T  G  P  F  D  I  W  G  Q  G  T  M  V  T  V  S  S  A  S 361 ACCAAGGGCCCATCGGTCTTCCCGCTAGCACCC 121  T  K  G  P  S  V  F  P  L  A  P Translation of VL-PB3-Tie1-phagemid.TXT (1-308) Universal code Total amino acid number: 102, MW = 11032 Max ORF: 1-306, 102 AA, MW = 11032   1 CAAGACATCCAGATGACCCAGTCTCCAGCCACCCTGTCTTTGTCTCCAGGGGAAAGAGCC (SEQ ID NO:25)   1  Q  D  I  Q  M  T  Q  S  P  A  T  L  S  L  S  P  G  E  R  A (SEQ ID NO:26)  61 ACCCTCTCCTGCAGGGCCAGTCAGAGTGTTAGCACCTACTTAGCCTGGTACCAACAGAAA  21  T  L  S  C  R  A  S  Q  S  V  S  T  Y  L  A  W  Y  Q  Q  K 121 CCTGGCCAGGCTCCCAGGCTTCTCATCTATGATGCATCCAACAGGGCCACTGGCATCCCA  41  P  G  Q  A  P  R  L  L  I  Y  D  A  S  N  R  A  T  G  I  P 181 GGCAGGTTCAGTGGCAGTGGGTCTGGGACAGACTTCACTCTCACCATCAGCAGCCTAGAG  61  G  R  F  S  G  S  G  S  G  T  D  F  T  L  T  I  S  S  L  E 241 GCTGAAGACTTTGCAGTTTATTACTGTCAGCAGCGTAGCAGCTGGCCGATCACCTTCGGC  81  A  E  D  F  A  V  Y  Y  C  Q  Q  R  S  S  W  P  I  T  F  G 301 CAAGGGAC 101  Q  G Translation of VH-PC6-Tie1-phagemid.TXT (1-429) Universal code Total amino acid number: 143, MW = 14727 Max ORF: 1-429, 143 AA, MW = 14727   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:27)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:28)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTCATTACGGTATGACTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  H  Y  G  M  T  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGTTATCTCTCCTTCTGGTGGCCAGACTGGTTAT  41  P  G  K  G  L  E  W  V  S  V  I  S  P  S  G  G  Q  T  G  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGGGTGGTGGC  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  G  G  G 301 TACGCAGCCTTTGACTACTGGGGCCAGGGAACCCTGGTCACCGTCTCAAGCGCCTCCACC 101  Y  A  A  F  D  Y  W  G  Q  G  T  L  V  T  V  S  S  A  S  T 361 AAGGGCCCATCGGTCTTCCCGCTAGCACCCTCCTCCAAGAGCACCTCTGGGGGCACAGCG 121  K  G  P  S  V  F  P  L  A  P  S  S  K  S  T  S  G  G  T  A 421 GCCCTGGGC 141  A  L  G Translation of VL-PC6-Tie1-phagemid.TXT (1-308) Universal code Total amino acid number: 102, MW = 11014 Max ORF: 1-306, 102 AA, MW = 11014   1 CAAGACATCCAGATGACCCAGTCTCCAGCCACCCTGTCTTTGTCTCCAGGGGAAAGAGCC (SEQ ID NO:29)   1  Q  D  I  Q  M  T  Q  S  P  A  T  L  S  L  S  P  G  E  R  A (SEQ ID NO:30)  61 ACCCTCTCCTGCAGGGCCAGTCAGAGTGTTAGCAGCTACTTAGCCTGGTACCAACAGAAA  21  T  L  S  C  R  A  S  Q  S  V  S  S  Y  L  A  W  Y  Q  Q  K 121 CCTGGCCAGGCTCCCAGGCTCCTCATCTATGATGCATCCAACAGGGCCACTGGCATCCCA  41  P  G  Q  A  P  R  L  L  I  Y  D  A  S  N  R  A  T  G  I  P 181 GCCAGGTTCAGTGGCAGTGGGTCTGGGACAGACTTCACTCTCACCATCAGCAGCCTAGAG  61  A  R  F  S  G  S  G  S  G  T  D  F  T  L  T  I  S  S  L  E 241 CCTGAAGATTTTGCAGTTTATTACTGTCAGCAGCGTAGCAACTGGCCTCTCACTTTCGGC  81  P  E  D  F  A  V  Y  Y  C  Q  Q  R  S  N  W  P  L  T  F  G 301 GGAGGGAC 101  G  G Translation of Reverse_Complement_VH-PD6-Tie1-phagemid.TXT (1-396) Universal code Total amino acid number: 132, MW = 14217 Max ORF: 1-396, 132 AA, MW = 14217   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:31)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:32)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTGCTTACCGTATGGAGTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  A  Y  R  M  E  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTTCTATCTATCCTTCTGGTGGCATTACTTATTAT  41  P  G  K  G  L  E  W  V  S  S  I  Y  P  S  G  G  I  T  Y  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGTCAAT  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  N 301 TACTATGATAGTAGTGGTTACGGTCCTATAGCTCCTGGACTTGACTACTGGGGCCAGGGA 101  Y  Y  D  S  S  G  Y  G  P  I  A  P  G  L  D  Y  W  G  Q  G 361 ACCCTGGTCACCGTCTCAAGCGCCTCCACCAAGGGC 121  T  L  V  T  V  S  S  A  S  T  K  G Translation of VL-PD6-Tie1-phagemid.TXT (1-308) Universal code Total amino acid number: 101, MW = 10731 Max ORF: 115-306, 64 AA, MW = 6731   1 CAAGACATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTAGGAGACAGAGTT (SEQ ID NO:33)   1  Q  D  I  Q  M  T  Q  S  P  S  S  L  S  A  S  V  G  D  R  V (SEQ ID NO:34)  61 ACCATCACTTGCCGGGCAAGTCAGGGCATTACCACTTATTTAGGCTGGTATTAGCAGAAA  21  T  I  T  C  R  A  S  Q  G  I  T  T  Y  L  G  W  Y  *  Q  K 121 CCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCACTTTGCAAAGTGGGGTCCCA  41  P  G  K  A  P  K  L  L  I  Y  A  A  S  T  L  Q  S  G  V  P 181 GCAAAGTTCAGCGGCAGTGGATCTGGGACACTTTTCACTCTCACCATCAGCGGTCTGCAA  61  A  K  F  S  G  S  G  S  G  T  L  F  T  L  T  I  S  G  L  Q 241 CCTGAAGATTCTGCAACTTACTACTGTCACCAGAGTTACAATACCCCTTGGACGTTCGGC  81  P  E  D  S  A  T  Y  Y  C  H  Q  S  Y  N  T  P  W  T  F  G 301 CAAGGGAC 101  Q  G Translation of VH-PD10-Tie1-phagemid.TXT (1-412) Universal code Total amino acid number: 136, MW = 14313 Max ORF: 181-411, 77 AA, MW = 8216   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:35)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:36)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTGGTTACGGTATGCATTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  G  Y  G  M  H  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGTTATCTCTCCTTCTGGTGGCCAGACTTGGTAG  41  P  G  K  G  L  E  W  V  S  V  I  S  P  S  G  G  Q  T  W  * 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGGCGGG  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  G  G 301 ACCAGTAACCCACTGTTTTACTGGGGCCAGGGAACCCTGGTCACCGTCTCAAGCGCCTCC 101  T  S  N  P  L  F  Y  W  G  Q  G  T  L  V  T  V  S  S  A  S 361 ACCAAGGGCCCATCGGTCTTCCCGCTAGCACCCTCCTCCAAGAGCACCTCTG 121  T  K  G  P  S  V  F  P  L  A  P  S  S  K  S  T  S Translation of VL-PD10-Tie1-phagemid.TXT (1-308) Universal code Total amino acid number: 102, MW = 11069 Max ORF: 1-306, 102 AA, MW = 11069   1 CAAGACATCCAGATGACCCAGTCTCCAGCCACCCTGTCTTTGTCTCCAGGGGAAAGAGCC (SEQ ID NO:37)   1  Q  D  I  Q  M  T  Q  S  P  A  T  L  S  L  S  P  G  E  R  A (SEQ ID NO:38)  61 ACCCTCTCCTGCAGGGCCAGTCAGAGTGTTAGCAGCTACTTAGCCTGGTACCAACAGAAA  21  T  L  S  C  R  A  S  Q  S  V  S  S  Y  L  A  W  Y  Q  Q  K 121 CCTGGCCAGGCTCCCAGGCTCCTCATCTATGATGCATCCAACAGGGCCACTGGCATCCCA  41  P  G  Q  A  P  R  L  L  I  Y  D  A  S  N  R  A  T  G  I  P 181 GCCAGGTTCAGTGGCAGTGGGTCTGGGACAGACTTCACTCTCACCATCAGCAGCCTAGAG  61  A  R  F  S  G  S  G  S  G  T  D  F  T  L  T  I  S  S  L  E 241 CCTGAAGATTTTGCAGTTTATTACTGTCAGCAGCGTAGCAACTGGCCTCCGACTTTTGGC  81  P  E  D  F  A  V  Y  Y  C  Q  Q  R  S  N  W  P  P  T  F  G 301 CAGGGGAC 101  Q  G Translation of VH-PD12-Tie1-phagemid.TXT (1-444) Universal code Total amino acid number: 148, MW = 15535 Max ORF: 1-444, 148 AA, MW = 15535   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:39)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:40)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTGGTTACGGTATGCATTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  G  Y  G  M  H  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGTTATCTCTCCTTCTGGTGGCCAGACTTCTTAT  41  P  G  K  G  L  E  W  V  S  V  I  S  P  S  G  G  Q  T  S  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGATAGG  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  D  R 301 CAGTATTACTATGGTTCGGGGAGTCTTGACTACTGGGGCCAGGGAACCCTGGTCACCGTC 101  Q  Y  Y  Y  G  S  G  S  L  D  Y  W  G  Q  G  T  L  V  T  V 361 TCAAGCGCCTCCACCAAGGGCCCATCGGTCTTCCCGCTAGCACCCTCCTCCAAGAGCACC 121  S  S  A  S  T  K  G  P  S  V  F  P  L  A  P  S  S  K  S  T 421 TCTGGGGGCACAGCGGCCCTGGGC 141  S  G  G  T  A  A  L  G Translation of VL-PD12-Tie1-phagemid.TXT (1-308) Universal code Total amino acid number: 102, MW = 11060 Max ORF: 1-306, 102 AA, MW = 11060   1 CAAGACATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTAGGAGACAGAGTC (SEQ ID NO:41)   1  Q  D  I  Q  M  T  Q  S  P  S  S  L  S  A  S  V  G  D  R  V (SEQ ID NO:42)  61 ACCGTCACTTGCCGGGCAAGTCAGAGCATTAGCAGTTATTTAAATTGGTATCAGCAGAAA  21  T  V  T  C  R  A  S  Q  S  I  S  S  Y  L  N  W  Y  Q  Q  K 121 CCAGGGAAAGCCCCTAAACTCCTGATCTATGCTGCATCCAGTTTGCAAAGTGGGGTCCCA  41  P  G  K  A  P  K  L  L  I  Y  A  A  S  S  L  Q  S  G  V  P 181 TCAAGGTTCAGTGGCGGTGGATCTGGGACAGATTTCACTCTCACCATCAGCAGTCTGCAA  61  S  R  F  S  G  G  G  S  G  T  D  F  T  L  T  I  S  S  L  Q 241 CCTGAAGATTTTGCAACTTATTTCTGTCTACAAGATTACAAATACCCGTGGACGTTCGGC  81  P  E  D  F  A  T  Y  F  C  L  Q  D  Y  K  Y  P  W  T  F  G 301 CAAGGGAC 101  Q  G Translation of Reverse_Complement_VH-PF3-Tie1-phagemid.TXT (1-375) Universal code Total amino acid number: 125, MW = 13201 Max ORF: 1-375, 125 AA, MW = 13201   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:43)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:44)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTATGTACGGTATGGGTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  M  Y  G  M  G  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGTTATCTCTCCTTCTGGTGGCCAGACTGCTTAT  41  P  G  K  G  L  E  W  V  S  V  I  S  P  S  G  G  Q  T  A  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGTGGCC  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  A 301 TTGCTCCTGGGCCACGCTTTTGATATCTGGGGCCAAGGGACAATGGTCACCGTCTCAAGC 101  L  L  L  G  H  A  F  D  I  W  G  Q  G  T  M  V  T  V  S  S 361 GCCTCCACCAAGGGC 121  A  S  T  K  G Translation of VL-PF3-Tie1-phagemid.TXT (1-308) Universal code Total amino acid number: 102, MW = 11162 Max ORF: 1-306, 102 AA, MW = 11162   1 CAAGACATCCAGATGACCCAGTCTCCTTCCACCCTGTCTGCATCTTTAGGAGACAGAGTC (SEQ ID NO:45)   1  Q  D  I  Q  M  T  Q  S  P  S  T  L  S  A  S  L  G  D  R  V (SEQ ID NO:46)  61 ACCATCACTTGCCGGGCCAGTGAGAGTATTAGTAGGTGGTTGGCCTGGTATCAGCAGAAA  21  T  I  T  C  R  A  S  E  S  I  S  R  W  L  A  W  Y  Q  Q  K 121 CCAGGGAAAGCCCCTAAGCTCCTGATGTATGAGGCATCCACTTTAGAAAGTGGGGTCCCA  41  P  G  K  A  P  K  L  L  M  Y  E  A  S  T  L  E  S  G  V  P 181 TCAAGGTTCACCGGCACTGGATCTGGGACAGAATTCACTCTCACCATCAGCAGCCTGCAG  61  S  R  F  T  G  T  G  S  G  T  E  F  T  L  T  I  S  S  L  Q 241 CCCGATGATTTTGCAACTTATTACTGTCAGCAGCGTAGCAACTGGCCCCTCACTTTCGGC  81  P  D  D  F  A  T  Y  Y  C  Q  Q  R  S  N  W  P  L  T  F  G 301 GAGGGAC 101  G  G Translation of VH-PF4-Tie1-phagemid.TXT (1-429) Universal code Total amino acid number: 143, MW = 14996 Max ORF: 1-429, 143 AA, MW = 14996   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:47)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:48)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTGCTTACATGATGTCTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  A  Y  M  M  S  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTTCTATCTATCCTTCTGGTGGCTATACTTATTAT  41  P  G  K  G  L  E  W  V  S  S  I  Y  P  S  G  G  Y  T  Y  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGGCTTA  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  G  L 301 CGGGGAGGTCCTGACTACTGGGGCCAGGGAACCCTGGTCACCGTCTCAAGCGCCTCCACC 101  R  G  G  P  D  Y  W  G  Q  G  T  L  V  T  V  S  S  A  S  T 361 AAGGGCCCATCGGTCTTCCCGCTAGCACCCTCCTCCAAGAGCACCTCTGGGGGCACAGCG 121  K  G  P  S  V  F  P  L  A  P  S  S  K  S  T  S  G  G  T  A 421 GCCCTGGGC 141  A  L  G Translation of VL-PF4-Tie1-phagemid.TXT (1-308) Universal code Total amino acid number: 102, MW = 10966 Max ORF: 1-306, 102 AA, MW = 10966   1 CAAGACATCCAGATGACCCAGTCTCCTTCCACCCTGTCTGCATATGTAGGAGACAGTGTC (SEQ ID NO:49)   1  Q  D  I  Q  M  T  Q  S  P  S  T  L  S  A  Y  V  G  D  S  V (SEQ ID NO:50)  61 ACCATCACTTGCCGGGCCAGTCAGAGTGTGAGAAGGTCGTTGGCCTGGTATCAGCAGAGA  21  T  I  T  C  R  A  S  Q  S  V  R  R  S  L  A  W  Y  Q  Q  R 121 CCAGGGAAAGCCCCCAAGTCCCTCATCTATAAGGCGTCTACTTTAGAGACTGGGGTCCCA  41  P  G  K  A  P  K  S  L  I  Y  K  A  S  T  L  E  T  G  V  P 181 CCAAGGTTCAGCGGCAGTGGATCTGGGACAGAATTCACTCTCACCATCAGCAGCCTGCAG  61  P  R  F  S  G  S  G  S  G  T  E  F  T  L  T  I  S  S  L  Q 241 CCTGAAGATTCTGCAATTTATTACTGCCAACAATATGGTAGTTTTCCGCTCACTTTCGGC  81  P  E  D  S  A  I  Y  Y  C  Q  Q  Y  G  S  F  P  L  T  F  G 301 GGAGGGAC 101  G  G Translation of VH-PG3-Tie1-phagemid.TXT (1-441) Universal code Total amino acid number: 147, MW = 15647 Max ORF: 1-441, 147 AA, MW = 15647   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:51)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:52)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTCATTACATGATGGTTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  H  Y  M  M  V  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTTCTATCTATCCTTCTGGTGGCTGGACTTATTAT  41  P  G  K  G  L  E  W  V  S  S  I  Y  P  S  G  G  W  T  Y  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGGCTGGAC  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  L  D 301 TACGGTGGTAATTCCGCCTACTTTGACTACTGGGGCCAGGGAACCCTGGTCACCGTCTCA 101  Y  G  G  N  S  A  Y  F  D  Y  W  G  Q  G  T  L  V  T  V  S 361 AGCGCCTCCACCAAGGGCCCATCGGTCTTCCCGCTAGCACCCTCCTCCAAGAGCACCTCT 121  S  A  S  T  K  G  P  S  V  F  P  L  A  P  S  S  K  S  T  S 421 GGGGGCACAGCGGCCCTGGGC 141  G  G  T  A  A  L  G Translation of VL-PG3-Tie1-phagemid.TXT (1-327) Universal code Total amino acid number: 109, MW = 11792 Max ORF: 1-327, 109 AA, MW = 11792   1 CAGAGCGTCTTGACTCAGCCGCACTCTGTGTCGGCCTCTCCGGGGAAGACGGTAACCATC (SEQ ID NO:53)   1  Q  S  V  L  T  Q  P  H  S  V  S  A  S  P  G  K  T  V  T  I (SEQ ID NO:54)  61 TCCTGCACCCGCAGCAGTGGCAACATTGCCAGCAACTTTGTCCAGTGGTACCAACAGCGC  21  S  C  T  R  S  S  G  N  I  A  S  N  F  V  Q  W  Y  Q  Q  R 121 CCGGGCAGTGTCCCCACCACTGTGATTTATGAAGATGACCGAAGACCCTCTGGGGTCCCT  41  P  G  S  V  P  T  T  V  I  Y  E  D  D  R  R  P  S  G  V  P 181 GATCGCTTTTCTGGCTCCATCGACAGTTCCTCCAACTCTGCTTTCCTCAGCATCTCTGGA  61  D  R  F  S  G  S  I  D  S  S  S  N  S  A  F  L  S  I  S  G 241 CTGAAGACTGAGGACGAGGCAGACTATTACTGTCAGTCTCATGATCGTACCACCCGTGCT  81  L  K  T  E  D  E  A  D  Y  Y  C  Q  S  H  D  R  T  T  R  A 301 TGGGTGTTCGGCGGAGGGACCAAGCTG 101  W  V  F  G  G  G  T  K  L Translation of VH-SA2-Tie1-phagemid.TXT (1-413) Universal code Total amino acid number: 137, MW = 14682 Max ORF: 1-411, 137 AA, MW = 14682   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:55)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:56)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTCGTTACACTATGATGTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  R  Y  T  M  M  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGGTATCTATCCTTCTGGTGGCGTTACTCTTTAT  41  P  G  K  G  L  E  W  V  S  G  I  Y  P  S  G  G  V  T  L  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGTCAAT  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  N 301 TACTATGATAGTAGTGGTTACGGTCCTATAGCTCCTGGACTTGACTACTGGGGCCAGGGA 101  Y  Y  D  S  S  G  Y  G  P  I  A  P  G  L  D  Y  W  G  Q  G 361 ACCCTGGTCACCGTCTCAAGCGCCTCCACCAAGGGCCCATCGGTCTTCCCGCT 121  T  L  V  T  V  S  S  A  S  T  K  G  P  S  V  F  P Translation of VL-SA2-Tie1-phagemid.TXT (1-339) Universal code Total amino acid number: 113, MW = 12358 Max ORF: 1-339, 113 AA, MW = 12358   1 CACAGTGCACAAGACATCCAGATGACCCAGTCTCCAGGCACCCTGTCTTTGTCTCCAGGG (SEQ ID NO:57)   1  H  S  A  Q  D  I  Q  M  T  Q  S  P  G  T  L  S  L  S  P  G (SEQ ID NO:58)  61 GAAAGAGCCACACTCTCCTGCAGGGCCAGTCGGAGTGTGATCATCAGCTACGTAGCCTGG  21  E  R  A  T  L  S  C  R  A  S  R  S  V  I  I  S  Y  V  A  W 121 TACCAGCAGAAACCTGGCCAGGCTCCCAGGCTCCTCATCTATGGAGCGTCCACCAGGGCC  41  Y  Q  Q  K  P  G  Q  A  P  R  L  L  I  Y  G  A  S  T  R  A 181 ACTGGCATCCCAGACAGGTTCAGTGGCAGTGGGTCTGGGACAGACTTCACTCTCACCATC  61  T  G  I  P  D  R  F  S  G  S  G  S  G  T  D  F  T  L  T  I 241 AGCAGACTGGAGCCTGAAGACTTTGCAGTGTATTTCTGTCAGCTTTATGGTAGGTCACCA  81  S  R  L  E  P  E  D  F  A  V  Y  F  C  Q  L  Y  G  R  S  P 301 CGGATCATCTTCGGCCAAGGGACACGACTGGAGATTAAA 101  R  I  I  F  G  Q  G  T  R  L  E  I  K Translation of VH-SA10-Tie1-phagemid.TXT (1-369) Universal code Total amino acid number: 123, MW = 13314 Max ORF: 1-369, 123 AA, MW = 13314   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:59)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:60)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTAATTACGTTATGGTTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  N  Y  V  M  V  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGGTATCTATCCTTCTGGTGGCCATACTAAGTAT  41  P  G  K  G  L  E  W  V  S  G  I  Y  P  S  G  G  H  T  K  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGTCAAT  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  N 301 TACTATGATAGTAGTGGTTACGGTCCTATAGCTCCTGGACTTGACTACTGGGGCCAGGGA 101  Y  Y  D  S  S  G  Y  G  P  I  A  P  G  L  D  Y  W  G  Q  G 361 ACCCTGGTC 121  T  L  V Translation of VL-SA10-Tie1-phagemid.TXT (1-339) Universal code Total amino acid number: 113, MW = 12445 Max ORF: 1-339, 113 AA, MW = 12445   1 CACAGTGCACAAGACATCCAGATGACCCAGTCTCCAGGCACCCTGTCTTTGTCTCCAGGG (SEQ ID NO:61)   1  H  S  A  Q  D  I  Q  M  T  Q  S  P  G  T  L  S  L  S  P  G (SEQ ID NO:62)  61 GAAAGAGCCACCCTCTTCTGCAGGGCCAGTCAGCGTGTTACCAGCAACTCCTTGGCCTGG  21  E  R  A  T  L  F  C  R  A  S  Q  R  V  T  S  N  S  L  A  W 121 TACCAGCAGAGACCTGGCCAGGCTCCCAGGCTCCTCATCTATGATGCATCCACCAGGGCC  41  Y  Q  Q  R  P  G  Q  A  P  R  L  L  I  Y  D  A  S  T  R  A 181 ACTGGCATCCCAGACCGCTTCAGTGGCAGTGGGTCGGGGAGGGACTTCACTCTCACCATC  61  T  G  I  P  D  R  F  S  G  S  G  S  G  R  D  F  T  L  T  I 241 AGCAGACTGGAGCCTGAAGATTTTGCAGTTTATTACTGTCAGCGATATGGTAGTTCAGTG  81  S  R  L  E  P  E  D  F  A  V  Y  Y  C  Q  R  Y  G  S  S  V 301 TTGTACTCTTTTGGCCAGGGGACGAAGTTGGAAATCACA 101  L  Y  S  F  G  Q  G  T  K  L  E  I  T Translation of VH-SB2-Tie1-phagemid.TXT (1-383) Universal code Total amino acid number: 127, MW = 13611 Max ORF: 1-381, 127 AA, MW = 13611   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:63)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:64)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTATTTACGGTATGGCTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  I  Y  G  M  A  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGTTATCTCTCCTTCTGGTGGCCAGACTTTTTAT  41  P  G  K  G  L  E  W  V  S  V  I  S  P  S  G  G  Q  T  F  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGTTTAC  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  Y 301 TACTACGGTATGGACGTCTGGGGCCAAGGGACCACGGTCACCGTCTCAAGCGCCTCCACC 101  Y  Y  G  M  D  V  W  G  Q  G  T  T  V  T  V  S  S  A  S  T 361 AAGGGCCCATCGGTCTTCCCGCT 121  K  G  P  S  V  F  P Translation of VL-SB2-Tie1-phagemid.TXT (1-333) Universal code Total amino acid number: 111, MW = 122 21 Max ORF: 1-333, 111 AA, MW = 12221   1 CACAGTGCACAAGACATCCAGATGACCCAGTCTCCAGCCACCCTGTCTTTGTCTCCAGGG (SEQ ID NO:65)   1  H  S  A  Q  D  I  Q  M  T  Q  S  P  A  T  L  S  L  S  P  G (SEQ ID NO:66)  61 GAAAGAGCCACCCTCTCCTGCAGGGCCAGTCAGAGTGTTAGCAGCTACTTAGCCTGGTAC  21  E  R  A  T  L  S  C  R  A  S  Q  S  V  S  S  Y  L  A  W  Y 121 CAACAAAAACCTGGCCAGGCTCCCAGGCTCCTCATTTATGATGCATCCAACAGGGCCACT  41  Q  Q  K  P  G  Q  A  P  R  L  L  I  Y  D  A  S  N  R  A  T 181 GGCATCCCAGCCAGGTTCAGTGGCAGTGGGTCTGAGACAGACTTCACTCTCACCATCAGC  61  G  I  P  A  R  F  S  G  S  G  S  E  T  D  F  T  L  T  I  S 241 AGCCTAGAGCCTGAAGATTTTGCAGTTTATTACTGTCAGCAGCGTAGCAAGTGGCCTCGG  81  S  L  E  P  E  D  F  A  V  Y  Y  C  Q  Q  R  S  K  W  P  R 301 ACTTTTGGCCAGGGGACCAAGCTGGAGATCAAA 101  T  F  G  Q  G  T  K  L  E  I  K Translation of VH-SB9-Tie1-phagemid.TXT (1-413) Universal code Total amino acid number: 137, MW = 14778 Max ORF: 1-411, 137 AA, MW = 14778   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:67)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:68)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTTCTTACGTTATGATGTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  S  Y  V  M  M  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGGTATCTATCCTTCTGGTGGCTGGACTTATTAT  41  P  G  K  G  L  E  W  V  S  G  I  Y  P  S  G  G  W  T  Y  Y 181 ACTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  T  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGTCAAT  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  N 301 TACTATGATAGTAGTGGTTACGGTCCTATAGCTCCTGGACTTGACTACTGGGGCCAGGGA 101  Y  Y  D  S  S  G  Y  G  P  I  A  P  G  L  D  Y  W  G  Q  G 361 ACCCTGGTCACCGTCTCAAGCGCCTCCACCAAGGGCCCATCGGTCTTCCCGCT 121  T  L  V  T  V  S  S  A  S  T  K  G  P  S  V  F  P Translation of VL-SB9-Tie1-phagemid.TXT (1-336) Universal code Total amino acid number: 112, MW = 12010 Max ORF: 1-336, 112 AA, MW = 12010   1 CACAGTGCACAAGACATCCAGATGACCCAGTCTCCATCCTCCCTGTCTGCATCTGTTGGA (SEQ ID NO:69)   1  H  S  A  Q  D  I  Q  M  T  Q  S  P  S  S  L  S  A  S  V  G (SEQ ID NO:70)  61 GATAGAGTCACCATCACTTGCCGGGCAAGTCAGAGTGTCAGCAGTCATTTAAGTTGGTTT  21  D  R  V  T  I  T  C  R  A  S  Q  S  V  S  S  H  L  S  W  F 121 CAGCAGAGACCAGGGAAAGCCCCCAACCTCCTGATCTATCATGCATCCAGTTTGCAAAGT  41  Q  Q  R  P  G  K  A  P  N  L  L  I  Y  H  A  S  S  L  Q  S 181 GGGGTCCCATCAAGGTTCAGTGGCAGTGGGTCTGGGACAGATTTCACGCTCACCATCAGC  61  G  V  P  S  R  F  S  G  S  G  S  G  T  D  F  T  L  T  I  S 241 AGTCTGCAACCTGAAGATTTTGCAACTTACTACTGTCAGCAGAGTTACGCTACTTCCTCG  81  S  L  Q  P  E  D  F  A  T  Y  Y  C  Q  Q  S  Y  A  T  S  S 301 ATCACCTTCGGCCAGGGGACACGACTGGACATTAAA 101  I  T  F  G  Q  G  T  R  L  D  I  K Translation of VH-SC2-Tie1-phagemid.TXT (1-413) Universal code Total amino acid number: 137, MW = 14650 Max ORF: 1-411, 137 AA, MW = 14650   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:71)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:72)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTCGTTACAAGATGAAGTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  R  Y  K  M  K  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGTTATCTATCCTTCTGGTGGCGGTACTGGTTAT  41  P  G  K  G  L  E  W  V  S  V  I  Y  P  S  G  G  G  T  G  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGTCAAT  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  N 301 TACTATGATAGTAGTGGTTACGGTCCTATAGCTCCTGGACTTGACTACTGGGGCCAGGGA 101  Y  Y  D  S  S  G  Y  G  P  I  A  P  G  L  D  Y  W  G  Q  G 361 ACCCTGGTCACCGTCTCAAGCGCCTCCACCAAGGGCCCATCGGTCTTCCCGCT 121  T  L  V  T  V  S  S  A  S  T  K  G  P  S  V  F  P Translation of VL-SC2-Tie1-phagemid.TXT (1-428) Universal code Total amino acid number: 142, MW = 15044 Max ORF: 1-426, 142 AA, MW = 15044   1 CACAGTGCACAGAGCGTCTTGACTCAGCCTGACTCCGTGTCTGGGTCTCCTGGAGAGTCG (SEQ ID NO:73)   1  H  S  A  Q  S  V  L  T  Q  P  D  S  V  S  G  S  P  G  E  S (SEQ ID NO:74)  61 ATCACCATCTCCTGCACTGGAAGCAGCAGAGACGTTGGTGGTTATAACTATGTCTCCTGG  21  I  T  I  S  C  T  G  S  S  R  D  V  G  G  Y  N  Y  V  S  W 121 TACCAACAACACCCAGGCAAAGCCCCCAAACTCTTGCTTTATGATGTCACTTATCGGCCC  41  Y  Q  Q  H  P  G  K  A  P  K  L  L  L  Y  D  V  T  Y  R  P 181 TCAGGGATTTCTGGTCGCTTCTCTGGCTCCAAGTCTGGCGACACGGCCTCCCTGACCATC  61  S  G  I  S  G  R  F  S  G  S  K  S  G  D  T  A  S  L  T  I 241 TCTGGGCTCCGGACTGAGGACGAGGCTGATTATTACTGCAGCTCATCTATAGGCACCAGG  81  S  G  L  R  T  E  D  E  A  D  Y  Y  C  S  S  S  I  G  T  R 301 ACTTATGTCTTCGGAAGTGGGACCAAGGTCACCGTCCTACGTCAGCCCAAGGCCAACCCC 101  T  Y  V  F  G  S  G  T  K  V  T  V  L  R  Q  P  K  A  N  P 361 ACTGTCACTCTGTTCCCGCCCTCCTCTGAGGAGCTCCAAGCCAACAAGGCCACACTAGTG 121  T  V  T  L  F  P  P  S  S  E  E  L  Q  A  N  K  A  T  L  V 421 TGTCTGAT 141  C  L Translation of VH-SC7-Tie1-phagemid.TXT (1-386) Universal code Total amino acid number: 128, MW = 13785 Max ORF: 1-384, 128 AA, MW = 13785   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:75)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:76)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTCGTTACGTTATGTATTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  R  Y  V  M  Y  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGTTATCTATCCTTCTGGTGGCGCTACTTATTAT  41  P  G  K  G  L  E  W  V  S  V  I  Y  P  S  G  G  A  T  Y  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGACGGGGA  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  R  G 301 AGTAGTGGTGCGTTTGACTACTGGGGCCAGGGAACCCTGGTCACCGTCTCAAGCGCCTCC 101  S  S  G  A  F  D  Y  W  G  Q  G  T  L  V  T  V  S  S  A  S 361 ACCAAGGGCCCATCGGTCTTCCCGCT 121  T  K  G  P  S  V  F  P Translation of VL-SC7-Tie1-phagemid.TXT (1-434) Universal code Total amino acid number: 144, MW = 15027 Max ORF: 1-432, 144 AA, MW = 15027   1 CACAGTGCACAGAGCGTCTTGACTCAGCCTGCCTCCGTGTCTGGGTCTCCTGGACAGTCG (SEQ ID NO:77)   1  H  S  A  Q  S  V  L  T  Q  P  A  S  V  S  G  S  P  G  Q  S (SEQ ID NO:78)  61 ATCACCATCTCCTGCACTGGAACCAGCAGTGACATTGGTCGTTATAACTATGCCTCCTGG  21  I  T  I  S  C  T  G  T  S  S  D  I  G  R  Y  N  Y  A  S  W 121 TACCAACAACGCCCAGGCAAATCCCCCAAACTCCTGATTTATGAGGTCAGTGATCGGCCC  41  Y  Q  Q  R  P  G  K  S  P  K  L  L  I  Y  E  V  S  D  R  P 181 TCAGGGGTTTCTAATCGCTTCTCTGGCTCCAAGTCTGGCAACACGGCCTCCCTGATCATC  61  S  G  V  S  N  R  F  S  G  S  K  S  G  N  T  A  S  L  I  I 241 TCTGGGCTCCAGGCTGAGGACGAGGCTGATTATTACTGCAGCTCATATTCAAGCACCAAC  81  S  G  L  Q  A  E  D  E  A  D  Y  Y  C  S  S  Y  S  S  T  N 301 AGTCTCCAAGTGGTATTCGGCGGAGGGACCAAGCTGAGCGTCCTAGGTCAGCCCAAGGCT 101  S  L  Q  V  V  F  G  G  G  T  K  L  S  V  L  G  Q  P  K  A 361 GCCCCCTCGGTCACTCTGTTCCCGCCCTCCTCTGAGGAGCTTCAAGCCAACAAGGCCACA 121  A  P  S  V  T  L  F  P  P  S  S  E  E  L  Q  A  N  K  A  T 421 CTGGTGTGTCTCAT 141  L  V  C  L Translation of VH-SC10-Tie1-phagemid.TXT (1-413) Universal code Total amino acid number: 137, MW = 14688 Max ORF: 1-411, 137 AA, MW = 14688   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:79)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:80)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTGCTTACGGTATGTCTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  A  Y  G  M  S  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGTTATCTATCCTTCTGGTGGCTGGACTTATTAT  41  P  G  K  G  L  E  W  V  S  V  I  Y  P  S  G  G  W  T  Y  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGTCAAT  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  N 301 TACTATGATAGTAGTGGTTACGGTCCTATAGCTCCTGGACTTGACTACTGGGGCCAGGGA 101  Y  Y  D  S  S  G  Y  G  P  I  A  P  G  L  D  Y  W  G  Q  G 361 ACCCTGGTCACCGTCTCAAGCGCCTCCACCAAGGGCCCATCGGTCTTCCCGCT 121  T  L  V  T  V  S  S  A  S  T  K  G  P  S  V  F  P Translation of VL-SC10-Tie1-phagemid.TXT (1-336) Universal code Total amino acid number: 112, MW = 12256 Max ORF: 1-336, 112 AA, MW = 12256   1 CACAGTGCACAAGACATCCAGATGACCCAGTCTCCAGGCACCCTGTCTTTGTCTCCAGGG (SEQ ID NO:81)   1  H  S  A  Q  D  I  Q  M  T  Q  S  P  G  T  L  S  L  S  P  G (SEQ ID NO:82)  61 GAAAGAGCCACCCTCTCCTGCAGGGCCAGTCAGAGTGTTAGCAGCAGCTACTTAGCCTGG  21  E  R  A  T  L  S  C  R  A  S  Q  S  V  S  S  S  Y  L  A  W 121 TACCAGCAGAAACCTGGCCAGGCTCCCAGGCTCCTCATCTATGGTGCATCCAGCAGGGCC  41  Y  Q  Q  K  P  G  Q  A  P  R  L  L  I  Y  G  A  S  S  R  A 181 ACTGGCATCCCAGACAGGTTCAGTGGCAGTGGGTCTGGGACAGACTTCACTCTCACCATC  61  T  G  I  P  D  R  F  S  G  S  G  S  G  T  D  F  T  L  T  I 241 AGCAGACTGGAGCCTGAAGATTTTGCAGTGTATTACTGTCAGCAGTATAATAACTGGCCT  81  S  R  L  E  P  E  D  F  A  V  Y  Y  C  Q  Q  Y  N  N  W  P 301 CGGACGTTCGGCCAAGGGACCAAGGTGGAAATCAAA 101  R  T  F  G  Q  G  T  K  V  E  I  K Translation of VH-SD11-Tie1-phagemid.TXT (1-395) Universal code Total amino acid number: 131, MW = 14005 Max ORF: 1-393, 131 AA, MW = 14005   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:83)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:84)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTGGTTACGCTATGTGGTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  G  Y  A  M  W  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTTCTATCTCTCCTTCTGGTGGCGCTACTGCTTAT  41  P  G  K  G  L  E  W  V  S  S  I  S  P  S  G  G  A  T  A  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGATGCG  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  D  A 301 GGGAGTTATTATTGGGGCTGGTTCGACCCCTGGGGCCAGGGAACCCTGGTCACCGTCTCA 101  G  S  Y  Y  W  G  W  F  D  P  W  G  Q  G  T  L  V  T  V  S 361 AGCGCCTCCACCAAGGGCCCATCGGTCTTCCCGCT 121  S  A  S  T  K  G  P  S  V  F  P Translation of VL-SD11-Tie1-phagemid.TXT (1-333) Universal code Total amino acid number: 111, MW = 12194 Max ORF: 1-333, 111 AA, MW = 12194   1 CACAGTGCACAAGACATCCAGATGACCCAGTCTCCAGCCACCTTGTCTTTGTCTCCAGGG (SEQ ID NO:85)   1  H  S  A  Q  D  I  Q  M  T  Q  S  P  A  T  L  S  L  S  P  G (SEQ ID NO:86)  61 GAAAGAGCCACCCTCTCCTGCAGGGCCAGTCAGAGTATTAGCAGCTACTTAGCCTGGTAC  21  E  R  A  T  L  S  C  R  A  S  Q  S  I  S  S  Y  L  A  W  Y 121 CAACAGAAACCTGGCCAGCCTCCCAGGCTCCTCATCTATGATGCATCCAGCAGGGTTACT  41  Q  Q  K  P  G  Q  P  P  R  L  L  I  Y  D  A  S  S  R  V  T 181 GGCATCCCAGCCAGGTTCAGTGGCAGTGGCTTTGGGACAGACTTCACTCTCACCATTAGT  61  G  I  P  A  R  F  S  G  S  G  F  G  T  D  F  T  L  T  I  S 241 AGCCTGGAGCCTGAAGATTTTGCAGTTTATTACTGTCTCCAGCGTAGCAGCTGGCCCCGA  81  S  L  E  P  E  D  F  A  V  Y  Y  C  L  Q  R  S  S  W  P  R 301 ACTTTTGGCCAGGGGACCAAGCTGGAGATCAAA 101  T  F  G  Q  G  T  K  L  E  I  K Translation of VH-SE11-Tie1-phagemid.TXT (1-413) Universal code Total amino acid number: 137, MW = 14670 Max ORF: 1-411, 137 AA, MW = 14670   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:87)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:88)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTGGTTACGTTATGTTTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  G  Y  V  M  F  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGGTATCTATCCTTCTGGTGGCTGGACTGTTTAT  41  P  G  K  G  L  E  W  V  S  G  I  Y  P  S  G  G  W  T  V  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGTCAAT  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  N 301 TACTATGATAGTAGTGGTTACGGTCCTATAGCTCCTGGACTTGACTACTGGGGCCAGGGA 101  Y  Y  D  S  S  G  Y  G  P  I  A  P  G  L  D  Y  W  G  Q  G 361 ACCCTGGTCACCGTCTCAAGCGCCTCCACCAAGGGCCCATCGGTCTTCCCGCT 121  T  L  V  T  V  S  S  A  S  T  K  G  P  S  V  F  P Translation of VL-SE11-Tie1-phagemid.TXT (1-333) Universal code Total amino acid number: 111, MW = 11962 Max ORF: 1-333, 111 AA, MW = 11962   1 CACAGTGCACAAGACATCCAGATGACCCAGTCTCCAGGCACCCTGTCTTTGTCTCCAGGG (SEQ ID NO:89)   1  H  S  A  Q  D  I  Q  M  T  Q  S  P  G  T  L  S  L  S  P  G (SEQ ID NO:90)  61 GAAAGAGCCACCCTCTCCTGCAGGGCCAGTCAGAGTGTTAGCAGCAGCTACTTAGCCTGG  21  E  R  A  T  L  S  C  R  A  S  Q  S  V  S  S  S  Y  L  A  W 121 TACCAGCAGAAACCTGGCCAGGCTCCCAGGCTCCTCATCTATGGTGCATCCAGCAGGGCC  41  Y  Q  Q  K  P  G  Q  A  P  R  L  L  I  Y  G  A  S  S  R  A 181 ACTGGCATCCCAGACAGGTTCAGTGGCAGTGGGTCTGGGACAGACTTCACTCTCACCATC  61  T  G  I  P  D  R  F  S  G  S  G  S  G  T  D  F  T  L  T  I 241 AGCAGACTGGAGCCTGAAGATTTTGCAGTGTATTACTGTCAGCAATATGGTAGCTCACGG  81  S  R  L  E  P  E  D  F  A  V  Y  Y  C  Q  Q  Y  G  S  S  R 301 ACGTTCGGCCAAGGGACCAACGTGGAAATCAAA 101  T  F  G  Q  G  T  N  V  E  I  K Translation of VH-SG4-Tie1-phagemid.TXT (1-395) Universal code Total amino acid number: 131, MW = 14168 Max ORF: 1-393, 131 AA, MW = 14168   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:91)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:92)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTTCTTACATGATGACTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  S  Y  M  M  T  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTTCTATCTATCCTTCTGGTGGCTATACTTATTAT  41  P  G  K  G  L  E  W  V  S  S  I  Y  P  S  G  G  Y  T  Y  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGGAGGG  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  G  G 301 TATGGCGACTCGTCATTTTTTTTTGACTACTGGGGCCAGGGAACCCTGGTCACCGTCTCA 101  Y  G  D  S  S  F  F  F  D  Y  W  G  Q  G  T  L  V  T  V  S 361 AGCGCCTCCACCAAGGGCCCATCGGTCTTCCCGCT 121  S  A  S  T  K  G  P  S  V  F  P Translation of VL-SG4-Tie1-phagemid.TXT (1-333) Universal code Total amino acid number: 111, MW = 11832 Max ORF: 1-333, 111 AA, MW = 11832   1 CACAGTGCACAAGACATCCAGATGACCCAGTCTCCAGCCACCCTGTCTGTGTCTCCAGGG (SEQ ID NO:93)   1  H  S  A  Q  D  I  Q  M  T  Q  S  P  A  T  L  S  V  S  P  G (SEQ ID NO:94)  61 GAAGGAGCCACCCTCTCTTGCAGGGCCAGTCGGAGTGTTGGCAGCAACTTAGCCTGGTAC  21  E  G  A  T  L  S  C  R  A  S  R  S  V  G  S  N  L  A  W  Y 121 CAGCAGAAGCCTGGCCAGGCTCCCAGGCTCCTCATCTATGATGCATCCACCAGGGCCACT  41  Q  Q  K  P  G  Q  A  P  R  L  L  I  Y  D  A  S  T  R  A  T 181 GGTATCCCCGCCAGGTTCAGTGGCAGTGGGTCTGGGACAAAGTTCACTCTCACCATCAGC  61  G  I  P  A  R  F  S  G  S  G  S  G  T  K  F  T  L  T  I  S 241 AGCCTCCAGTCTGAAGATTTTGCAGTTTATTACTGTCAGCAGCGTAGCAATTGGCCTCTC  81  S  L  Q  S  E  D  F  A  V  Y  Y  C  Q  Q  R  S  N  W  P  L 301 ACTTTCGGCGGAGGGACCAAGGTGGAGATCAAA 101  T  F  G  G  G  T  K  V  E  I  K Complete sequence VH-SG9 not known Translation of VL-SG9-Tie1-phagemid.TXT (1-428) Universal code Total amino acid number: 142, MW = 14993 Max ORF: 1-426, 142 AA, MW = 14993   1 CACAGTGCACAGAGCGTCTTGACTCAGCCTGCCTCCGTGTCTGGGTCTCCTGGACAGTCG (SEQ ID NO:95)   1  H  S  A  Q  S  V  L  T  Q  P  A  S  V  S  G  S  P  G  Q  S (SEQ ID NO:96)  61 ATCACCATCTCCTGCACTGGAACCAGCAGTGACGTTGGTGATGATAACTATGTCTCCTGG  21  I  T  I  S  C  T  G  T  S  S  D  V  G  D  D  N  Y  V  S  W 121 TACCAACAACACCCAGACAAAGCCCCCAAACTCATGATTTATGAGGTCAGTTATCGGCCC  41  Y  Q  Q  H  P  D  K  A  P  K  L  M  I  Y  E  V  S  Y  R  P 181 TCAGGGGTTTCTAATCGCTTCTCTGGCTCCAAGTCTGGCAACACGGCCTCCCTGACCATC  61  S  G  V  S  N  R  F  S  G  S  K  S  G  N  T  A  S  L  T  I 241 TCTGGGCTCCAGACTGAGGACGAGGCTGATTATTATTGCGGCTCATATCGCGTCAGCAGC  81  S  G  L  Q  T  E  D  E  A  D  Y  Y  C  G  S  Y  R  V  S  S 301 TCCTATGTCTTCGGAACTGGGACCAAGGTCACCGTCCTAGGTCAGCCCAAGGCCAACCCC 101  S  Y  V  F  G  T  G  T  K  V  T  V  L  G  Q  P  K  A  N  P 361 ACTGTCACTCTGTTCCCGCCCTCCTCTGAGGAGCTCCAAGCCAACAAGGCCACACTAGTG 121  T  V  T  L  F  P  P  S  S  E  E  L  Q  A  N  K  A  T  L  V 421 TGTCTGAT 141  C  L Translation of VH-SG10-Tie1-phagemid.TXT (1-363) Universal code Total amino acid number: 121, MW = 13390 Max ORF: 1-363, 121 AA, MW = 13390   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:97)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:98)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTCGTTACAAGATGTTTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  R  Y  K  M  F  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGTTATCTATCCTTCTGGTGGCCCTACTATGTAT  41  P  G  K  G  L  E  W  V  S  V  I  Y  P  S  G  G  P  T  M  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGGGATG  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  G  M 301 GTCCGTGGATATAGTGGCTACGATTACCCTTTCTTGGACTACTGGGGCCAGGGAACCCTG 101  V  R  G  Y  S  G  Y  D  Y  P  F  L  D  Y  W  G  Q  G  T  L 361 GTC 121  V Translation of VL-SG10-Tie1-phagemid.TXT (1-333) Universal code Total amino acid number: 111, MW = 11981 Max ORF: 1-333, 111 AA, MW = 11981   1 CACAGTGCACAAGACATCCAGATGACCCAGTCTCCATCTTCCCTGTCTGCATCTGTAGGG (SEQ ID NO:99)   1  H  S  A  Q  D  I  Q  M  T  Q  S  P  S  S  L  S  A  S  V  G (SEQ ID NO:100)  61 GACAGAGTCACCATCACTTGCCGAGCAAGTCAGACCATTAGCAGCTATTTAAATTGGTAT  21  D  R  V  T  I  T  C  R  A  S  Q  T  I  S  S  Y  L  N  W  Y 121 CAGCAGAAGCCAGGGAAAGCCCCTAAGCTCCTGATCTATGCTGCATCCAGTTTGCAAAGT  41  Q  Q  K  P  G  K  A  P  K  L  L  I  Y  A  A  S  S  L  Q  S 181 GGGGTCCCATCAAGGTTCAGTGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAGC  61  G  V  P  S  R  F  S  G  S  G  S  G  T  D  F  T  L  T  I  S 241 AGTCTGCAACCTGAAGATTTTGCAACTTACTACTGTCAACAGAGTTACAGTACCCCTCGT  81  S  L  Q  P  E  D  F  A  T  Y  Y  C  Q  Q  S  Y  S  T  P  R 301 ACGTTCGGCCAAGGGACCAAGGTGGAAATCAAA 101  T  F  G  Q  G  T  K  V  E  I  K Translation of VH-SH1-Tie1-phagemid.TXT (1-386) Universal code Total amino acid number: 128, MW = 13767 Max ORF: 1-384, 128 AA, MW = 13767   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:101)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:102)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTGCTTACCAGATGGTTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  A  Y  Q  M  V  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTTCTATCTATCCTTCTGGTGGCTGGACTTATTAT  41  P  G  K  G  L  E  W  V  S  S  I  Y  P  S  G  G  W  T  Y  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGGCACG  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  G  T 301 CACCTCCCGGGGGTTGACTACTGGGGCCAGGGAACCCTGGTCACCGTCTCAAGCGCCTCC 101  H  L  P  G  V  D  Y  W  G  Q  G  T  L  V  T  V  S  S  A  S 361 ACCAAGGGCCCATCGGTCTTCCCGCT 121  T  K  G  P  S  V  F  P Translation of VL-SH1-Tie1-phagemid.TXT (1-339) Universal code Total amino acid number: 113, MW = 12225 Max ORF: 1-339, 113 AA, MW = 12225   1 CACAGTGCACAAGACATCCAGATGACCCAGTCTCCAGGCACCCTGTCTTTGTCTCCAGGG (SEQ ID NO:103)   1  H  S  A  Q  D  I  Q  M  T  Q  S  P  G  T  L  S  L  S  P  G (SEQ ID NO:104)  61 GAAAGAGCCACCCTCTCCTGCAGGGCCAGTCAGAGTGTTAGCAGCAGCTACTTAGCCTGG  21  E  R  A  T  L  S  C  R  A  S  Q  S  V  S  S  S  Y  L  A  W 121 TACCAGCAGAAACCTGGCCAGGCTCCCAGGCTCCTCATCTATGGTGCATCCAGCAGGGCC  41  Y  Q  Q  K  P  G  Q  A  P  R  L  L  I  Y  G  A  S  S  R  A 181 ACTGGCATCCCAGACAGGTTCAGTGGCAGTGGGTCTGGGACAGACTTCACTCTCACCATC  61  T  G  I  P  D  R  F  S  G  S  G  S  G  T  D  F  T  L  T  I 241 AGCAGACTGGAGCCTGAAGATTTTGCAGTGTATTACTGTCAGCAGTATGGTAGCTCCCCC  81  S  R  L  E  P  E  D  F  A  V  Y  Y  C  Q  Q  Y  G  S  S  P 301 ATGTACACTTTTGGCCAGGGGACCAAGCTGGAGATCAAA 101  M  Y  T  F  G  Q  G  T  K  L  E  I  K Translation of VH-SH4-Tie1-phagemid.TXT (1-339) Universal code Total amino acid number: 113, MW = 12481 Max ORF: 1-339, 113 AA, MW = 12481   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:105)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:106)  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTTCTTACAAGATGGGTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  S  Y  K  M  G  W  V  R  Q  A 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTTCTATCTATCCTTCTGGTGGCTGGACTCATTAT  41  P  G  K  G  L  E  W  V  S  S  I  Y  P  S  G  G  W  T  H  Y 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCAAGAGTACTA  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  L 301 CTACACTACTTTGACTACTGGGGCCAGGGAACCCTGGTC 101  L  H  Y  F  D  Y  W  G  Q  G  T  L  V Translation of VL-SH4-Tie1-phagemid.TXT (1-415) Universal code Total amino acid number: 138, MW = 14287 Max ORF: 1-414, 138 AA, MW = 14287   1 CACAGTGCACAGAGCGTCTTGACTCAGCCTGCCTCCGTGTCTGGGTCTCCTGGACAGTCG (SEQ ID NO:107)   1  H  S  A  Q  S  V  L  T  Q  P  A  S  V  S  G  S  P  G  Q  S (SEQ ID NO:108)  61 ATCACCATCTCCTGCACTGGAACCAGCAGTGACGTTGGTGGTTATAAATATGTCTCCTGG  21  I  T  I  S  C  T  G  T  S  S  D  V  G  G  Y  K  Y  V  S  W 121 TACCAACAGCACCCAGGCAAAGCCCCCAAACTCATTATTTCTGACGTCAATAATCGGCCC  41  Y  Q  Q  H  P  G  K  A  P  K  L  I  I  S  D  V  N  N  R  P 181 TCAGGGGTTTCTGATCGCTTCTCTGGCTCCAAGTCTGGCAACACGGCCTCCCTGACCATC  61  S  G  V  S  D  R  F  S  G  S  K  S  G  N  T  A  S  L  T  I 241 TCTGGGCTCCAGGCTGAGGACGACGGTGATTATTACTGCAGTTCCTACGCAAGTAGTTCC  81  S  G  L  Q  A  E  D  D  G  D  Y  Y  C  S  S  Y  A  S  S  S 301 TATACAAGCAGTACCACTTGGGTGTTCGGCGGGGGGACCAAGCTGACCGTCCTAGGTCAG 101  Y  T  S  S  T  T  W  V  F  G  G  G  T  K  L  T  V  L  G  Q 361 CCCAAGGCTGCCCCCTTGGTCACTCTGTTCCCACCCTCCTCTGAGGAGCTTCAAG 121  P  K  A  A  P  L  V  T  L  F  P  P  S  S  E  E  L  Q Translation of Reverse_Complement_K2086117 (1-471) Universal code Total amino acid number: 157, MW = 16967 Max ORF: 1-471, 157 AA, MW = 16967 T-G2-Tie1heavy ---------------------------Fr1------------------------------   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:109)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:110) ----------------Fr1----------|....CDR1......|-----Fr2-------  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTTCTTACAAGATGGGTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  S  Y  K  M  G  W  V  R  Q  A -------------Fr2----------|...........CDR2.................. 121 CCTGGTAGAGGTTTGGAGTGGGTTTCTTCTATCTATCCTTCTGGTGGCTGGACTCATTAT  41  P  G  R  G  L  E  W  V  S  S  I  Y  P  S  G  G  W  T  H  Y ......CDR2.......|-----------------Fr3---------------------- 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y ------------------------Fr3--------------------------|.CDR3. 241 TTGCAGATGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCAAGAGTACTA  81  L  Q  M  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  V  L .......CDR3......|--------------Fr4----------------- 301 CTACACTACTTTGACTACTGGGGCCAGGGAACCCTGGTCACCGTCTCAAGCGCCTCCACC 101  L  H  Y  F  D  Y  W  G  Q  G  T  L  V  T  V  S  S  A  S  T 361 AAGGGCCCATCGGTCTTCCCCCTGGCACCCTCCTCCAAGAGCACCTCGGGGGCACAGCGG 121  K  G  P  S  V  F  P  L  A  P  S  S  K  S  T  S  G  A  Q  R 421 CCCTGGGCTGCCTGGTCAAGGACTACTTCCCGCGATACCGGTGACGGTGTC 141  P  W  A  A  W  S  R  T  T  S  R  D  T  G  D  G  V Translation of C3-G2_pUCrev (1-325) Universal code Total amino acid number: 108, MW = 11191 Max ORF: 1-324, 108 AA, MW = 11191 T-G2-Tie1-lambda-light 2a2.272A12/DPL11 ----------------------------Fr1-----------------------------   1 CAGAGCGTCTTGACTCAGCCTGCCTCCGTGTCTGGGTCTCCTGGACAGTCGATCACCATC (SEQ ID NO:111)   1  Q  S  V  L  T  Q  P  A  S  V  S  G  S  P  G  Q  S  I  T  I (SEQ ID NO:112) -Fr1-|.....................CDR1................|----Fr2-----  61 TCCTGCACTGGAACCAGCAGTGACGTTGGTGGTTATAAATATGTCTCCTGGTACCAACAG  21  S  C  T  G  T  S  S  D  V  G  G  Y  K  Y  V  S  W  Y  Q  Q -------------Fr2----------------|.........CDR2.......|-Fr3-- 121 CACCCAGGCAAAGCCCCCAAACTCATTATTTCTGACGTCAATAATCGGCCCTCAGGGGTT  41  H  P  G  K  A  P  K  L  T  T  S  D  V  N  N  R  P  S  G  V ----------------------------Fr3----------------------------- 181 TCTGATCGCTTCTCTGGCTCCAAGTCTGGCAACACGGCCTCCCTGACCATCTCTGGGCTC  61  S  D  R  F  S  G  S  K  S  G  N  T  A  S  L  T  I  S  G  L ---------------Fr3-----------|..............CDR3............ 241 CAGGCTGAGGACGACGGTGATTATTACTGCAGTTCCTACGCAAGTAGTTCCTATACAAGC  81  Q  A  E  D  D  G  D  Y  Y  C  S  S  Y  A  S  S  S  Y  T  S ....CDR3...|----Fr4------ 301 AGTACCACTTGGGTGTTCGGCGGGG 101  S  T  T  W  V  F  G  G Translation of DNAMAN12 (1-425) Universal code Total amino acid number: 141, MW = 14855 Max ORF: 1-423, 141 AA, MW = 14855 T-E3-Tie1-heavy ---------------------------Fr1------------------------------   1 GAAGTTCAATTGTTAGAGTCTGGTGGCGGTCTTGTTCAGCCTGGTGGTTCTTTACGTCTT (SEQ ID NO:113)   1  E  V  Q  L  L  E  S  G  G  G  L  V  Q  P  G  G  S  L  R  L (SEQ ID NO:114) --------------Fr1------------|.....CDR1.....|------Fr2------  61 TCTTGCGCTGCTTCCGGATTCACTTTCTCTATGTACGGTATGGTTTGGGTTCGCCAAGCT  21  S  C  A  A  S  G  F  T  F  S  M  Y  G  M  V  W  V  R  Q  A ---------------Fr2--------|..............CDR2............... 121 CCTGGTAAAGGTTTGGAGTGGGTTTCTGTTATCTCTCCTTCTGGTGGCAATACTGGTTAT  41  P  G  K  G  L  E  W  V  S  V  I  S  P  S  G  G  N  T  G  Y ........CDR2.....|------------------Fr3--------------------- 181 GCTGACTCCGTTAAAGGTCGCTTCACTATCTCTAGAGACAACTCTAAGAATACTCTCTAC  61  A  D  S  V  K  G  R  F  T  I  S  R  D  N  S  K  N  T  L  Y --------------------------Fr3------------------------|.CDR3. 241 TTGCAGGTGAACAGCTTAAGGGCTGAGGACACTGCAGTCTACTATTGTGCGAGAGCCCCA  81  L  Q  V  N  S  L  R  A  E  D  T  A  V  Y  Y  C  A  R  A  P .............CDR3.........|--------------Fr4---------------- 301 CGTGGATACAGCTATGGTTACTACTACTGGGGCCAGGGAACCCTGGTCACCGTCTCAAGC 101  R  G  Y  S  Y  G  Y  Y  Y  W  G  Q  G  T  L  V  T  V  S  S 361 GCCTCCACCAAGGGCCCATCGGTCTTCCCGCTAGCACCCTCCTCCAAGAGCACCTCTGGG 121  A  S  T  K  G  P  S  V  F  P  L  A  P  S  S  K  S  T  S  G 421 GGCAC 141  G Translation of C1-E3_pUCrev (1-322) Universal code Total amino acid number: 107, MW = 11650 Max ORF: 1-321, 107 AA, MW = 11650 T-E3-Tie1-kappa-light DPK4/A20+ jk5 -----------------------------Fr1----------------------------   1 GACATCCAGATGACCCAGTCTCCACTCTCCCTGTCTGCATCTGTAGGAGACAGAGTCACC (SEQ ID NO:115)   1  D  I  Q  M  T  Q  S  P  L  S  L  S  A  S  V  G  D  R  V  T (SEQ ID NO:116) --Fr1---|.............CDR1...............|-------Fr2--------  61 ATCACTTGCCGGGCGAGTCAGGGCATTGGCCATTATTTAGCCTGGTATCAGCAGAAACCA  21  I  T  C  R  A  S  Q  G  I  G  H  Y  L  A  W  Y  Q  Q  K  P -----------Fr2------------|.........CDR2.......|----Fr3----- 121 GGGAAAGTTCCTAAGCTCCTGATCTATACTGCATCCACTTTGCAATCAGGGGTCCCATCT  41  G  K  V  P  K  L  L  I  Y  T  A  S  T  L  Q  S  G  V  P  S -----------------------------Fr3---------------------------- 181 CGGTTCAGTGGCAGTGGATCTGGGACAGATTTCACTCTCACCATCAACAGCCTGCAGCCT  61  R  F  S  G  S  G  S  G  T  D  F  T  L  T  I  N  S  L  Q  P -----------Fr3---------|..........CDR3.........|-----Fr4---- 241 GAGGATGTTGCAACTTATTACTGTCAACAGTTTAATAGTTACCCTCACACCTTCGGCCAA  81  E  D  V  A  T  Y  Y  C  Q  Q  F  N  S  Y  P  H  T  F  G  Q ----------Fr4--------- 301 GGGACACGACTGGATATTAAAC 101  G  T  R  L  D  I  K

Example 4 Alignment

Tables 3 and 4 the list CDR and FR regions of exemplary antibodies, the sequences of which are listed herein.

The sequences listed in Table 3 correspond to an amino-terminal portion of the variable heavy chain sequences of, respectively, SEQ ID NO:4, SEQ ID NO:16, SEQ ID NO:20, SEQ ID NO: 24, SEQ ID NO:28, SEQ ID NO:40, SEQ ID NO:44, SEQ ID NO:48, SEQ IS NO:52, SEQ ID NO:60, SEQ ID NO:102, SEQ ID NO:56, SEQ ID NO:64, SEQ ID NO:68, SEQ ID NO:80, SEQ ID NO:72, SEQ ID NO:76, SEQ ID NO:84, SEQ ID NO:88, SEQ ID NO:98, SEQ ID NO:106, SEQ ID NO:110, SEQ ID NO:114.

The sequences listed in Table 4 correspond to an amino-terminal portion of the variable light chain sequences of, respectively, SEQ ID NO:6, SEQ ID NO:18, SEQ ID NO:22, SEQ ID NO:26, SEQ ID NO:30, SEQ ID NO:42, SEQ ID NO:46, SEQ ID NO:50, SEQ ID NO:54, SEQ ID NO:62, SEQ ID NO:104, SEQ ID NO:58, SEQ ID NO:66, SEQ ID NO:70, SEQ ID NO:82, SEQ ID NO:74, SEQ ID NO:78, SEQ ID NO:86, SEQ ID NO:90, SEQ ID NO:100, SEQ ID NO:108, SEQ ID NO:112, SEQ ID NO:116.

TABLE 3 Heavy Chain Sequences Isolate name H-FR1 H-CDR1 FR2 H-CDR2 H-FR3 H-CDR3 p-A1 EVQLLESGGGLVQPGGS IYKMS WVRQAPGKGLEWVS SIYPSGGQTKYADSVKG RFTISRDNSKNTLYLQMNSLR VNYYDSSGYGPIAPGLDY LRLSCAASGFTFS AEDTAVYYCAR p-A10 EVQLLESGGGLVQPGGS SYKMG WVRQAPGKGLEWVS WIYPSGGGTTYADSVKG RFTISRDNSKNTLYLQMNSLR VNYYDSSGYGPIAPGLDY LRLSCAASGFTFS AEDTAVYYCAR p-B1 EVQLLESGGGLVQPGGS RYPMV WVRQAPGKGLEWVS VISPSGGQTFYADSVKG RFTISRDNSKNTLYLQMNSLR GVLTTAFDI LRLSCAASGFTFS AEDTAVYYCAR p-B3 EVQLLESGGGLVQPGGS RYGMH WVRQAPGKGLEWVS VISPSGGMTYYADSVKG RFTISRDNTKNTLYLQMNSLR VGATGPFDI LRLSCAASGFTFS AEDTAVYYCAR p-C6 EVQLLESGGGLVQPGGS HYGMT WVRQAPGKGLEWVS VISPSGGQTGYADSVKG RFTISRDNSKNTLYLQMNSLR GGYAAFDY LRLSCAASGFTFS AEDTAVYYCAG p-D12 EVQLLESGGGLVQPGGS GYGMH WVRQAPGKGLEWVS VISPSGGQTSYADSVKG RFTISRDNSKNTLYLQMNSLR DRQYYYGSGSLDY LRLSCAASGFTFS AEDTAVYYCAR p-F3 EVQLLESGGGLVQPGGS MYGMG WVRQAPGKGLEWVS VISPSGGQTAYADSVKG RFTISRDNSKNTLYLQMNSLR VALLLGHAFDI LRLSCAASGFTFS AEDTAVYYCAR p-F4 EVQLLESGGGLVQPGGS AYMMS WVRQAPGKGLEWVS SIYPSGGYTYYADSVKG RFTISRDNSKNTLYLQMNSLR GLRGGPDY LRLSCAASGFTFS AEDTAVYYCAR p-G3 EVQLLESGGGLVQPGGS HYMMV WVRQAPGKGLEWVS SIYPSGGWTYYADSVKG RFTISRDNSKNTLYLQMNSLR LDYGGNSAYFDY LRLSCAASGFTFS AEDTAVYYCAR s-A10 EVQLLESGGGLVQPGGS NYVMV WVRQAPGKGLEWVS GIYPSGGHTKYADSVKG RFTISRDNSKNTLYLQMNSLR VNYYDSSGYGPIAPGLDY LRLSCAASGFTFS AEDTAVYYCAR s-H1 EVQLLESGGGLVQPGGS AYQMV WVRQAPGKGLEWVS SIYPSGGWTYYADSVKG RFTISRDNSKNTLYLQMNSLR GTHLPGVDY LRLSCAASGFTFS AEDTAVYYCAR s-A2 EVQLLESGGGLVQPGGS RYTMM WVRQAPGKGLEWVS GIYPSGGVTLYADSVKG RFTISRDNSKNTLYLQMNSLR VNYYDSSGYGPIAPGLDY LRLSCAASGFTFS AEDTAVYYCAR s-B2 EVQLLESGGGLVQPGGS IYGMA WVRQAPGKGLEWVS VISPSGGQTFYADSVKG RFTISRDNSKNTLYLQMNSLR VYYYGMDV LRLSCAASGFTFS AEDTAVYYCAR s-B9 EVQLLESGGGLVQPGGS SYVMM WVRQAPGKGLEWVS GIYPSGGWTYYTDSVKG RFTISRDNSKNTLYLQMNSLR VNYYDSSGYGPIAPGLDY LRLSCAASGFTFS AEDTAVYYCAR s-C10 EVQLLESGGGLVQPGGS AYGMS WVRQAPGKGLEWVS VIYPSGGWTYYADSVKG RFTISRDNSKNTLYLQMNSLR VNYYDSSGYGPIAPGLDY LRLSCAASGFTFS AEDTAVYYCAR s-C2 EVQLLESGGGLVQPGGS RYKMK WVRQAPGKGLEWVS VIYPSGGGTGYADSVKG RFTISRDNSKNTLYLQMNSLR VNYYDSSGYGPIAPGLDY LRLSCAASGFTFS AEDTAVYYCAR s-C7 EVQLLESGGGLVQPGGS RYVMY WVRQAPGKGLEWVS VIYPSGGATYYADSVKG RFTISRDNSKNTLYLQMNSLR RGSSGAFDY LRLSCAASGFTFS AEDTAVYYCAR s-D11 EVQLLESGGGLVQPGGS GYAMW WVRQAPGKGLEWVS SISPSGGATAYADSVKG RFTISRDNSKNTLYLQMNSLR DAGSYYWGWFDP LRLSCAASGFTFS AEDTAVYYCAR s-E11 EVQLLESGGGLVQPGGS GYVMF WVRQAPGKGLEWVS GIYPSGGWTVYADSVKG RFTISRDNSKNTLYLQMNSLR VNYYDSSGYGPIAPGLDY LRLSCAASGFTFS AEDTAVYYCAR s-G10 EVQLLESGGGLVQPGGS RYKMF WVRQAPGKGLEWVS VIYPSGGPTMYADSVKG RFTISRDNSKNTLYLQMNSLR GMVRGYSGYDYPFLDY LRLSCAASGFTFS AEDTAVYYCAR s-H4 EVQLLESGGGLVQPGGS SYKMG WVRQAPGKGLEWVS SIYPSGGWTHYADSVKG RFTISRDNSKNTLYLQMNSLR VLLHYFDY LRLSCAASGFTFS AEDTAVYYCAR G2 EVQLLESGGGLVQPGGS SYKMG WVRQAPGRGLEWVS SIYPSGGWTHYADSVKG RFTISRDNSKNTLYLQMNSLR VLLHYFDY LRLSCAASGFTFS AEDTAVYYCAR E3 EVQLLESGGGLVQPGGS MYGMV WVRQAPGKGLEWVS VISPSGGNTGYADSVKG RFTISRDNSKNTLYLQVNSLR APRGYSYGYYY LRLSCAASGFTFS AEDTAVYYCAR

TABLE 4 Light Chain Sequences Isolate name L-FR1 L-CDR1 L-FR2 L-CDR2 L-FR3 L-CDR3 p-A1 QDIQMTQSPGTLSLSPGERATLSC RASQSVSSSYLA WYQQKPGQAPRLLIY GASSRAT GIPDRFSGSGSGTDFT QQYGSSRWT LTISRLEPEDFAVYYC p-A10 QDIQMTQSPGTLSLSPGERATLSC RASQSVSSSYLA WYQQKPGQAPRLLIY GASSRAT GIPDRFSGSGSGTDFT QQYGSSPWT LTISRLEPEDFAVYYC p-B1 QDIQMTQSPSSLSASVGDRVTITC RASQNINSYLN WYQQKPGQAPKLLIY AASNLET AVPSRFSGSGSGTDFT QQFNTYPLT LTISSLQPEDFATYYC p-B3 QDIQMTQSPATLSLSPGERATLSC RASQSVSTYLA WYQQKPGQAPRLLIY DASNRAT GIPGRFSGSGSGTDFT QQRSSWPIT LTISSLEAEDFAVYYC p-C6 QDIQMTQSPATLSLSPGERATLSC RASQSVSSYLA WYQQKPGQAPRLLIY DASNRAT GIPARFSGSGSGTDFT QQRSNWPLT LTISSLEAEDFAVYYC p-D12 QDIQMTQSPSSLSASVGDRVTVTC RASQSISSYLN WYQQKPGKAPKLLIY AASSLQS GVPSRFSGGGSGTDFT LQDYKYPWT LTISSLQPEDFAVYYC p-F3 QDIQMTQSPSTLSASLGDRVTITC PASESISRWLA WYQQKPGKAPKLLMY EASTLES GVPSRFTGTGSGTEET QQRSNWPLT LTISSLQPDDFATYYC p-F4 QDIQMTQSPSTLSAYVGDSVTITC RASQSVRRSLA WYQQKPGKAPKSLIY KASTLET GVPPRFSGSGSGTEET QQYGSEPLT LTISSLQPEDSAIYYC p-G3 QSVLTQPHSVSASPGKTVTISC TRSSGNIASNFVQ WYQQRPGSVPTTVIY EDDRRPS GVPFRFSGSIDSSSNS QSHDRTTPAWV AFLSISGLKTEDEADYYC s-A10 QDIQMTQSPGTLSLSPGERATLFC RASQRVTSNSLA WYQQRPGQAPRLLIY DASTRAT GIPFRFSGSGSGRDET QRYGSSVLYS LTISRLEPEDFAVYYC s-H1 QDIQMTQSPGTLSLSPGERATLSC RASQSVSSSYLA WYQQKPGQAPRLLIY GASSRAT GIPFRFSGSGSGTDFT QQYGSSPMYT LTISRLEPEDFAVYYC s-A2 QDIQMTQSPGTLSLSPGERATLSC PASRSVIISYVA WYQQKPGQAPRLLIY GASTRAT GIPFRFSGSGSGTDFT QLYGRSPRII LTISRLEPEDFACYFC s-B2 QDIQMTQSRATLSLSPGERATLSC RASQSVSSYLA WYQQKPGQAPRLLIY DASNRAT GIPARFSGSGSETDFT QQRSKWPRT LTISSLEPEDFAVYYC s-B9 QDIQMTQSPSSLSASVGDRVTITC RASQSVSSHLS WFQQRPGKAPNLLIY HASSLQS GVPSRFSGSGSGTDFT QQSYATSSIT LTISSLQPEDFATYYC s-C10 QDIQMTQSPGTLSLSPGERATLSC RASQSVSSSYLA WYQQKPGQAPRLLIY GASSRAT GIPFRFSGSGSGTDFT QQYNNWPRT LTISRLEPEDFAVYYC s-C2 QSVLTQPDSVSGSPGESITISC TGSSRDVGGYNYVS WYQQHPGKAPKLLLY DVTYRPS GISGRFSGSKSGDTAS SSSIGTRTYV LTISGLRTEDEADYYC s-C7 QSVLTQPASVSGSPGQSITISC TGTSSDIGRYNYAS WYQQRPGKSPKLLIY EVSDRPS GVSNRFSGSKSGNTAS SSYSSTNSLQVV LIISGLQAEDEADYYC s-D11 QDIQMTQSRATLSLSPGERATLSC RASQSISSYLA WYQQKPGQPPRLLIY DASSRVT GIPARFSGSGEGTDFT LQRSSWPRT LTISSLEPEDFAVYYC s-E11 QDIQMTQSPGTLSLSPGERATLSC RASQSVSSSYLA WYQQKPGQAPRLLIY GASSRAT GIPFRFSGSGSGTDFT QQYGSSRT LTISRLEPEDFAVYYC s-G10 QDIQMTQSPSSLSASVGDRVTITC RASQTISSYLN WYQQKPGKAPKLLIY AASSLQS GVPSRFSGSGSGTDFT QQSYSTPRT LTISSLQPEDFATYYC s-H4 QSVLTQPASVSGSPGQSITISC TGTSSDVGGYKYVS WYQQHPGKAPKLIIS DVNNRPS GVSFRFSGSKSGNTAS SSYASSSYTSSTTWV LTISGLQAEDDGDYYC G2 QSVLTQPASVSGSPGQSITISC TGTSSDVGGYKYVS WYQQHPGKAPKLIIS DVNNRPS GVSFRFSGSKSGNTAS SSYASSSYTSSTTWV LTISGLQAEDDGDYYC E3 DIQMTQSPLSLSASVGDRVTITC RASQGIGHYLA WYQQKPGKVPKLLIY TASTLQS GVPSRFSGSGSGTDFT QQFNSYPHT LTINSLQPEDVATYYC

Example 5 Sequence Alignment of B2 and D11

B2 and D11 are both antagonists of Tie1 since they counteract the agonistic activity of E3 in the BaF3 activation assay. B2 and D11 both have a kappa light chain and are similar in sequence (8 amino acid differences):

Example 6 Inhibition of Tube Formation by HUVECS Cells Using Anti Tie1 E3-IgG

To demonstrate the ability of E3 to inhibit angiogenesis in vitro, purified E3 was tested for its ability to inhibit tube formation by human umbilical cord endothelial cells (HUVECS). Human Umbilical vein endothelial cells (HUVEC) were obtained by treating fresh human umbilical cord veins with Trypsin-EDTA (1×) (Gibco/Invitrogen) for 20-25 minutes at 37° C. The cells were cultured in a T-25 flask coated with attachment factor (AF), (Cascade Biologics) in RPMI 1640 medium supplemented with 10% FCS, 0.4% BBE, 1% 1-glutamin, 1% penicillin/streptomycin. Primary cultures were detached with warm Trypsin-EDTA and used when confluent at the second or third passage. The cells were maintained in a proliferative state by culturing them in a split ratio 1:2 at an approximate density of the monolayer of about 60-80%. To dissociate the cells, HUVEC monolayers were treated with trypsin/EDTA (500 l/dish) at 37° C. for 3 min. Trypsin activity was stopped by adding 3 volumes of complete RPMI medium. The cells were carefully scraped, separated by repeated pipetting, and finally washed with PBS.

After 2 passages HUVECs were seeded in their culture medium (40.10³/50 μl/well of a 96-well plate) on a collagen gel (50 μl of collagen 11.5 mg/ml) prepared by mixing 7.5 volumes of 2 mg/ml collagen (Collagen R; Serva, Heidelberg, Germany), 1 volume of 10×MEM, 1.5 volume of NaHCO₃ (15.6 mg/ml) and ˜1 volume of NaOH to adjust the pH to 7.4. After 1 h 30, the culture medium was then discarded and the cells were covered with a new layer of collagen (1.5 mg/ml, new preparation, 50 μl/well). After polymerization of the gel, culture medium was added to each well in presence or in absence of E3 antibody (1 ng/ml to 10 μg/ml). The assay was performed with a streptavidin antibody used as a control (from 1 ng/ml to 10 μg/ml). The total length of the tube network on the culture surface was quantified at ×40 magnification by the METAVUE™ Software (Universal Imaging Corporation). Results from triplicate wells were expressed as mean vessel area per field±SEM (relative units). Each assay was performed at least three times.

E3 is a potent inhibitor of tube formation by HUVECS even at a concentration of 10 ng/ml. The control anti streptavidin has no effect on the ability of HUVECS to form tubes. This results indicates that E3 can inhibit one aspect of angiogenesis.

Example 7 Immunohistochemical Analysis of E3 Binding to Matched Tumor and Normal Tissue Sections

To evaluate the binding of E3 to Tie1 in primary tumor and normal tissue the antibody was produced as an IgG and biotin labeled. The E3 antibody and two other anti Tie1 antibodies B2 and D11 were reformatted as full length IgG molecules. Nucleic acids encoding these IgGs were transiently transfected into HEK293T cells. Plasmid preparations for transient cell transfections were performed using the HP-GENELUTE™ MIDI prep kit (Sigma, cat. no. NA0200). HEK293T cells (GenHunter Corp. cat. no. Q401) were seeded 24 hours before transfection; 6×10⁶ cells were plated per 10-cm culture dish. Transfections were carried out using LIPOFECTAMINE™ 2000 reagent (Invitrogen, cat. no. 11668019) following the manufacturer's instructions. Five micrograms of plasmid DNA was used per 10-cm dish. Cells were cultured in DMEM (Invitrogen, cat. no. 31966021) supplemented with 10% “ultra-low IgG” fetal calf serum (Invitrogen, cat. no. 16250078), at 37° C., 5% CO₂, in a water saturated atmosphere. Conditioned media were harvested 72 hours and 144 hours after transfection, pooled and sterile filtered.

One hundred microliters of Protein A beads (rProtein A Sepharose 4 Fast Flow, Amersham Biosciences, cat. no. 17-1279-01) equilibrated in PBS were added to the cell culture supernatants, and these were rotated overnight at 4° C., e.g., in 50 ml tubes. The beads were collected by centrifugation, transferred to a 96-well filter plate (UNI-FILTER 800 GF/B, Whatman, cat. no. 7700-2803) and washed extensively with PBS using a vacuum manifold (Macherey Nagel, cat. no. 760681). Elution of the antibodies was achieved by resuspending the beads in 400 μl of 12.5 mM citric acid. After a 30 to 60 second incubation, the bead eluates were collected, using the vacuum manifold, into the wells of a 96-well collection plate (UNIPLATE 750, Whatman, cat. no. 7701-5750). Each well of the collection plate contained 60 μl of 1 M HEPES pH 7.5 buffer to immediately neutralize the eluted fractions. The elution step was performed twice to maximize antibody recovery. The eluted samples were then dialyzed against PBS using dialysis cassettes (Slide-A-Lyser Dialysis Cassettes, MWCO 10,000, Pierce, cat. no. 66380) and protein concentration was determined from the absorbance at 280 nm assuming that a 1 mg/ml solution has an absorbance of 1.35. The quality of the preparations was analyzed by reducing and non-reducing SDS-PAGE.

The Tie-1 antibodies were biotinylated using the EZ-link Sulfo-NHS-SS-Biotin (Pierce, Cat. 21331). For Tie-1/Fc and Tie-1-His, the reaction was performed for 2 hours on ice in 50 mM sodium carbonate buffer, pH 9.6, in the presence of a 5-fold molar excess of biotinylating agent. For the antibodies, the reaction was performed for 2 hours on ice in PBS, in the presence of a 15-fold molar excess of EZ-link Sulfo-NHS-SS-Biotin. The reaction was stopped by the addition of Tris-HCl, pH 7.5 (50 mM final concentration) followed by a 1-hour incubation on ice. Samples were then dialyzed against PBS.

Various normal and tumor tissue sections were stained with biotinylated antibodies. A mouse monoclonal anti-Tie1 antibody (7e8) (Alitalo laboratory, University of Helsinki) was used as a positive control. Sections without primary antibody served as negative control. All samples were fresh frozen tissues and staining was performed with the TSA-kit (Perkin-Elmer Life Sciences). After acetone fixation (10-20 min, −20° C.) the slides were treated with 0.73% H₂O₂ for 10 min to reduce endogenous peroxidase activity followed by blocking for 30 min with TNB buffer. Sections (5-10 mm thick) were incubated with primary antibodies (10 μg/ml) overnight at 4° C. Sections with the mouse monoclonal anti-tie1 antibody (7e8) were treated with biotinylated anti-mouse antibodies (VectaStain) before the addition of streptavidin-HRP. Signal was amplified by using a TSA kit and the visualized by AEC (235 ml NaAc, 15 ml AEC (stock solution: 1600 mg 3-amino-9-ethyl-carbazole and 480 ml N-dimethylformamide), 250 μl H₂O₂).

In general, Tie-1 expression was upregulated in tumor tissue when compared with matching normal tissue. However, in the tumor tissues the anti Tie1 antibodies stained other structures in addition to the vessels. Furthermore, some tissue specificity in the expression of certain epitopes was observed. For example, the E3 antibody stained vessels in the lung and kidney but not in the skin while the B2 antibody stained vessels very faintly in other normal tissues than in the breast. Shedding of the ectodomain of Tie-1 into the tumor tissues can explain observed differences.

In skin tissue, the E3, B2, and D11 antibodies stained blood vessels very faintly whereas the murine 7e8 control antibody gave a clear staining in the normal skin. In melanoma tissue, the 7e8 antibody stained vessels only but the E3, B2, and D11 antibodies also stained other surrounding structures. The staining pattern was similar with all three of the E3, B2, and D11 antibodies.

In lung tissue, we observed that the E3 antibody stained especially clearly the large veins in the lung, whereas D11 and 7e8 gave a faint staining. B2 did not stain the same veins. The expression of Tie-1 was dramatically upregulated in lung carcinoma and all the antibodies stained vessels more strongly in samples with lung carcinoma than in samples from normal lung. In the lung tumors, the E3, B2, and D11 antibodies stained structures other than vessels.

In kidney, the E3 and D11 antibodies stained kidney tubules in addition to the vessels. B2 gave only very faint staining of either tubules or vessels while 7e8 stained only vessels. In hypernephroma tissue, only the E3 antibody gave a clear staining.

In breast, E3 gave the brightest staining in the veins and capillaries of the mammary tissue, B2 and 7e8 gave a similar staining while D11 stained those structures rather faintly. In breast carcinoma the Tie-1 expression was substantially upregulated, and the E3, B2, and D11 antibodies stained also other structures in addition to vessels.

Example 8 Binding to Mouse Endothelial Cell Lines of Anti Tie1 E3-IgG Using Flow Cytometry

We evaluated if E3 cross reacts with mouse Tie1 in situ and thus if we can evaluate E3 activity in mouse tumor xenograft models binding to mouse endothelial cells was tested and compared with human and transfected cell lines.

Specific binding of the Tie-1 antibodies and of control Mabs to mouse endothelial cells was measured by flow cytometry analysis (FACSscan, Becton Dickinson, Oxnard, Epics, Coulter). Mouse endothelial cell lines MS1, Le-2 (Alitalo) Bend3, SVEC (ATCC, Rockville) and Tie-1 transfected Le-2 cells (Alitalo) were stained. Cell staining was modified from existing protocols. About 200,000 cells were used in each experiment: after trypsinization, cells were washed one time in PBS and resuspended PBS, 10% Heat inactivated human serum (incubation buffer). To test specificity, antibodies were incubated at different dilutions for 1 h at room temperature. Cells were spun down by centrifugation for 3 min at 611 g. Between incubations cells were washed twice with PBS. Then relevant biotinylated antibodies (A2 against streptavidin, E3 against Tie-1, were added and incubated for 1 h at room temperature). This was followed by incubation with Strepatvidin-R-phycoerythrin (Dako, Glostrup, Denmark) for 1 hour at room temperature in incubation buffer. After the final incubation step bound antibodies were detected by means of flow cytometry on a FACSCan and Epics Altra (Becton Dickinson, Oxnard, Coulter,) and results analyzed.

Intracellular Tie-1 was measured as described above, except for the addition of Saponin to the incubation buffer to a final concentration of 0.1% during incubations. The anti-Tie-1 antibody E3 binds to mouse endothelial cell lines indicating a cross reactivity of E3 with mouse and human Tie1 in situ. The binding pattern in mouse cell lines detected by flow cytometry is different from the binding pattern in HUVEC in that in mouse cells there is a greater cell surface staining than that compared to primary human endothelial cell lines.

Example 9 Determination of Anti Tie1 E3-IgG Binding to Human Platelets Using Flow Cytometry

Binding experiments with a purified polyclonal goat antiserum against Tie-1 (R&D systems) had showed binding to human platelets in a previous study (Tsiamis et al., 2000). The conclusion form this study was that platelets represent a large pool of Tie-1 immunoreactivity which could present a problem for development of Tie1 as a therapeutic target. To determine if the antibody E3 binds to platelets we performed flow cytometric analysis on both activated and inactivated platelets and compared the staining pattern with the purified anti Tie1 polyclonal serum.

To avoid platelet activation, human platelets were isolated from plasma of healthy donors using the platelet GelSep kit (Biocytex, Marseille, France) kit according to the guidelines of the manufacturer. Platelets were activated by the addition of thrombin to a final concentration of 0.8 U/ml. To distinguish activated from non-activated platelets double staining was performed with Tie-1 antibodies/control antibodies and antibody CD42 (total platelets) or CD62 (activated platelets).

After preparation, platelets were resuspended in buffer 2 of the GelSep kit, 10% heat inactivated human serum (incubation buffer) and incubated for 1 hour. To test specificity, biotinylated antibodies human anti-Tie1 (E3), human anti-streptavidin (A2), human anti-FITC and goat anti-Tie (R&D systems) were incubated with 500 000 platelets per test for 1 hour at different dilutions (2 μg/ml, 10 μg/ml) for 1 h at room temperature. Platelets were spun down by centrifugation for 10 min at 611 g. Between incubations platelets were washed twice with Buffer 1 of the GelSep kit. Then, Strepatvidin-R-phycoerythrin together with anti-CD42-PercP or anti-CD62-PercP were incubated for 30 minutes at room temperature in incubation buffer After the last incubation and washing detection of bound antibodies was performed by means of flow cytometry on a FACS scan and Epics Altra (Becton Dickinson, Oxnard, Coulter,) and results analyzed. Cells were gated on SSC and anti-CD42-PercP for the total platelets in case non-activated platelets were used and on SSC and anti-CD62-PercP for the activated platelets.

The polyclonal goat anti-Tie-1 antibody indeed binds to platelets under the conditions tested. This binding is lower when platelets are activated. In contrast, the human anti-Tie1 antibody E3 shows no significant binding to total platelets, nor to activated platelets.

Example 10 Assessment of Tie1 Immunoreactivity in Human Platelets Using Immunoprecipitation with Anti Tie1 E3-IgG (Paula Henderikx, Laetitia Devy)

A previous study with a purified polyclonal goat antiserum against Tie-1 (R&D Systems) had showed binding to human platelets (Tsiamis et al., 2000). The conclusion from this study was that platelets represent a large pool of Tie-1 immunoreactivity which could present a problem for development of Tie1 as a therapeutic target. To exclude the possibility that the antibody E3 binds to platelets immunoprecipitation of lysates prepared from platelets and HUVECS were performed. Both, activated and inactivated platelets were tested. Anti-Tie-1 antibodies B2, D11, E3, the goat polyclonal AF619 (R&D) and negative control antibodies anti-FITC and anti-Streptavidin were used. HUVECS were retrieved from culture dishes by trypsinization and platelets were prepared with the platelet GelSep kit (Biocytex, Marseille, France) kit according to the guidelines of the manufacturer. Per immunoprecipitation experiment 3-5e10⁶ and 3e10⁸ cells platelets were used for each antibody tested. Platelets and cells were washed with PBS and spun down at 1400 rpm for 4 minutes and supernatant was removed. Then cells were lysed in 1 ml lysis buffer containing 50 mM Tris HCL pH 7.5, 150 mM NaCl, 0.5% Deoxycholic acid (DOC) and 0.5% NP-40 for 5 minutes. The lysed cells were spin down for 10 minutes at 14.000 rpm and 5 μg/ml antibody was added to the supernatant and incubated at 4° C. on a rotator. 100 μl/sample protein A beads (Uppsala, Sweden) were washed 3 times with lysis buffer (centrifugation speed: 15 seconds, 2000 rpm) then cell lysates incubated with antibody were added for 30 minutes 4° C. Then beads were washed three times with washing buffer containing 50 mM Tris HCL pH 7.5, 400 mM NaCl, 0.5% DOC, 0.5% NP-40. Finally, beads are spun down and the pellets was resuspended in an equal amount in sample buffer to perform SDS-page and Western blotting. In Western blotting Tie-1 was detected with the polyclonal goat anti-Tie-1 antibody. The conclusions of this study are that E3 is able to immune precipitate Tie-1 in HUVEC but not in platelets.

Example 11 Distribution of Tie1 in HUVECS Cells Determined by Staining with Anti Tie1 E3-IgG

We analyzed the staining pattern of E3 in HUVECS using confocal microscopy. HUVEC were trypsinised, washed with PBS and spotted at a density of 60 000 cells on a gelatine coated microscope slide and incubated for 24 hours in a humidified incubator at 37° C. Cells were air dried and fixed with 4% paraformaldehyde for 20 minutes at room temperature. The slides were washed with PBS. The slides were incubated with 10% Heat inactivated human serum (incubation buffer).

For measuring specific binding to Tie-1, biotinylated antibody E3 and biotinylated negative control antibody A2 were used at a concentration of 10 μg/ml and incubated for 1 hour at room temperature. Slides were washed twice with PBS. Then, Strepatvidin-R-phycoerythrin (Dako, Glostrup, Denmark) was added and incubated for 1 hour at room temperature. After the last incubation and washing detection of bound antibodies was performed by means of confocal microscopy.

E3 binds specifically to HUVEC as detected by confocal microscopy. The staining is pre-dominantly located inside of the cell which suggests a large intracellular pool of Tie1 relative to a smaller pool of cell surface localized Tie1. The localization of E3 was consistent with co-localization of Tie1 with a cytoskeletal protein.

Example 12 Conversion of Somatic Mutations Positioned in the Framework Region of Anti Tie1 E3 to Germline Residues

To reduce potential immunogenicity of E3 in humans, all non germline amino acid residues in the LC framework regions were corrected back to germline. An initial analysis was performed which aligned the LC of E3 with a database containing all kappa and lambda light chain germline genes. The LC of E3 was shown to have closest homology to DPK4 and three substitutions in E3 relative to the germline framework regions were identified.

We constructed a germlined version of E3 in which the LC framework regions were altered to include sequences identical to the DPK4 germline framework regions. The germlined E3 antibody was constructed by engineering a nucleic acid encoding the desired sequence. Changes to nucleic acids encoding the E3 LC variable domain were made by PCR and other standard molecular biological techniques and verified by nucleic acid sequencing.

The germlined E3 sequence is as follows:

(SEQ ID NO:159) DIQMTQSPSSLSASVGDRVTITCRASQGIGHYLAWYQQKPGKVPKLLIYT ASTLQSGVPSRFSGSGSGTDFTLTISSLQPEDVATYYCQQFNSYPHTFGQ GTRLEIK

The altered positions are underscored.

We produced the germlined version of the E3 antibody as both a soluble Fab and as an IgG. The Fab cassette of the positive sFAB-expressing clone was PCR amplified with oligonucleotides, ligated into a mammalian expression vector containing the human IgG4 Fc region and electroporated into XL1 Blue MRF′ cells. The prokaryotic ribosomal binding sequence and gene three leader sequence were replaced with a mammalian internal ribosomal entry and heavy chain leader sequences. Reformatted antibody clones were sequenced to confirm accuracy following the cloning procedure. Endotoxin-free DNA was prepared and used for transient transfection studies.

Example 13 Production and Testing of Germlined Anti Tie1 E3-Fab for Binding to Recombinant Tie1-Fc in ELISA

To evaluate if the conversion of any of the somatic mutations in the framework of E3 back to germline residues had any effect on binding activity the soluble Fabs were produced. The soluble expression vector containing the parental E3 Fab and the germlined E3 Fab construct were grown overnight at 30° C. in 2×TY broth containing 100 μg/ml ampicillin and 2% glucose and use 4 ml of this overnight culture to inoculate 400 ml of 2×TY broth containing 100 μg/ml ampicillin and 0.1% glucose. Cells were grow at 37° C. until an OD₆₀₀ of 0.8-1.0, 1 mM IPTG was added and the culture was maintained at 30° C. for 4 hours. The cultures were spun down at 4,000 rpm for 15 min at 4° C. The supernatants were discarded and resuspend the pellets resuspended in 4.8 ml of ice cold TES buffer (0.2 M Tris-HCl, 0.5 mM EDTA, 0.5 M sucrose, pH 8.0) containing proteases inhibitors (protease inhibitor cocktail tablets [Roche]: dissolve 1 tablet in 1 ml of water and dilute 50-times in TES buffer). Transfer to 50 ml Falcon tubes and place on ice for 5-10 min. During this incubation, wash the centrifugation bottles with 5.25 ml TES:H₂O (1:3) containing proteases inhibitors and add this to the cells. Incubate for 20 more min on ice. Spin at 3000 g for 15 min at 4° C. and transfer the supernatants into new centrifugation tubes. Resuspend the cell pellets in 6 ml TES containing 15 mM MgSO₄ and proteases inhibitors and incubate on ice for 15 min. Centrifuge at 3000 g for 15 min at 4° C. Transfer the supernatants into the centrifugation tubes and spin at 8000 g for 20 min at 4° C. Collect the supernatants and dialyze against PBS. The Fabs were purified by metal chelate chromatography. Incubate the dialyzed periplasmic extracts with 1 ml of TALON™ Metal Affinity Resin (Clontech) and rotate at room temperature for 2 hours. Transfer the beads into empty gravity column (Poly-Prep chromatography columns, Bio-Rad, Cat. 731-1550). Wash the beads with 5 mM imidazole in PBS and elute the Fabs with 150 mM imidazole in PBS. Dialyze against PBS using dialysis cassettes (SLIDE-A-LYSER™ Dialysis Cassettes, MWCO 10,000, Pierce, cat. no. 66380) and determine the protein concentration from the absorbance at 280 nm assuming that a 1 mg/ml solution has an absorbance of 0.86. The quality of the preparations can be analyzed by reducing and non-reducing SDS-PAGE.

Wells of an IMMULON™ 2 HB plate coated overnight with 500 ng or 50 ng of purified recombinant human Tie-1-Fc target antigen per 100 microliters 0.1 M sodium bicarbonate buffer, pH 8.5. Parental E3, E3 germlined (E3g) or a negative control soluble Fab were loaded into wells at either 5 micrograms or 1 microgram per 100 microliters of PBST. Recombinant human Tie-1-Fc target antigen is dissolved in an appropriate amount of acetic acid and subsequently diluted into 0.1 M sodium bicarbonate buffer, pH 9.6 at final concentrations of 500 ng and 50 ng per 100 microliters. After addition of the target antigen to the wells the microtitre plate is incubated overnight at 4° C. The plate is subsequently washed 5 times with PBST and blocked with 1% BSA in PBS at 37° C. for 2 hours. The plate is again washed plate times with wash buffer, PBST and 100 microliters per well of purified Fab at 5 or 1 micrograms per 100 microliter PBST was added followed by incubation at room temperature for 1 hour. After washing plate 7 times with PBST 100 microliters of a 1:5000 dilution of anti-sFab-HRP in PBST was added (Pierce Product #31414). After washing the wells seven times 100 microliters TMB-H₂O₂ solution was added to each well and the plate read at 630 nm in an ELISA. Both E3 and germlined E3 bound to the recombinant human Tie-1-Fc target antigen by this assay.

Example 14 Production and Testing of Germlined Anti Tie1-E3-Fab for Binding to Recombinant Human Tie1 in BIAcore

Recombinant purified human Tie1-Fc antigen (Stock 2.45 mg/ml) was biotinylated using the EZ-link Sulfo-NHS-SS-Biotin (Pierce, Cat. 21331). The reaction was performed for 2 hours on ice in 50 mM sodium carbonate buffer, pH 9.6, in the presence of a 5-fold molar excess of biotinylating agent and was stopped by the addition of Tris-HCl, pH 7.5 (50 mM final concentration) followed by a 1-hour incubation on ice. Samples were then dialyzed against PBS. The antigen was then diluted 1/100 fold in HBS and was then captured onto a streptavidin chip. This was coated to a density of 830 RU (resonance units). All analysis was performed in HBS buffer. The parental Fab E3 and germlined E3 Fab were prepared as described above. A stock solution of 0.587 mg/ml (11740 nM) was diluted 1/587 in HBS+BSA to obtain a stock of 20 nM and the germlined Fab E3 0.025 mg/ml (500 nM) was diluted 1/25 in HBS+BSA to obtain a stock of 20 nM. Serial dilutions were made of each Fab preparation to obtain 10 nM, 5 nM, 2.5 nM, and 1.25 nM solutions. For the association phase samples were injected at 30 μl/min for 4 minutes using kinject program. This was followed by a 10 minutes dissociation phase, any remaining sample was stripped from the Tie-1 Fc surface at a flow of 50 μl/min with a single injection of 5 mM NaOH+1M NaCl for 18 seconds. All samples were run and analyzed in duplicate.

Sensorgrams were analyzed using the simultaneous ka/kd fitting program with 1:1 model in the BIAEVALUATION™ software 3.1. From the analysis we can see that the germlining of the E3 antibody has had minimal effect on the binding activity of the antibody.

TABLE 5 Comparison of the binding affinity of parental and germlined E3 Fab E3 Fab Tie-1 Fc ka (1/Ms) kd (1/s) KD(1) nM parental Human 3.00E+05 6.10E−04 2.0 germlined Human 3.00E+05 1.02E−03 3.4

Example 15 Comparison of Affinity of Germlined Anti Tie1 E3-IgG to Parental Anti Tie1 E3 for Binding to Recombinant Human Tie1 Using BIAcore

In order to evaluate if the binding behavior had been affected in any way by the conversion of the somatic mutations back to germline residues, the germlined antibody was produced and tested as an IgG. The germlined E3-IgG construct used to transiently transfect HEK293T cells and purified.

The germlined E3 IgG1 stock solution 0.63 mg/ml was diluted 1/50 in a buffer of pH4.5 and the parental E3 IgG1 stock solution 0.56 mg/ml (2143-001) was diluted 1/50 in a buffer of pH 4.5. The IgG were directly coated onto a CM5 chip. The surface of the chips was activated with a 7 minute pulse of 0.05M NHS/0.2M EDC and the IgG was flowed over until 780 RU germlined E3-IgG and 728 non germlined E3 IgG was coated onto the surface. All flow cells were subsequently deactivated with a 7 minute pulse of 1M ethanolamine hydrochloride pH 8.5. All analysis was performed in HBS buffer. Purified recombinant human Tie-1 Fc was diluted 1/28.7 in HBS to obtain a 400 nM stock solution. Serial dilutions were made to obtain 200 nM, 100 nM, 50 nM and 25 nM Tie-1 Fc stocks. For analysis of the association phase samples were injected at 30 μl/min for 8.3 minutes using kinject program. This was followed by a 40 minutes dissociation phase. Any antigen remaining associated to the surface was stripped from the IgG surface at a flow of 50 μl/min with two injections of 10 mM glycine pH 1.5 for 30 seconds. All samples were run and analyzed in duplicate

Sensorgrams were analyzed using the simultaneous ka/kd fitting program with 1:1 model in the BIAEVALUATION™ software 3.1. Germlining had minimal impact on the binding activity of the E3 IgG with respect to human Tie1 Fc.

TABLE 6 Comparison of the binding affinity of parental and germlined E3 IgG E3 IgG Tie-1 Fc ka (1/Ms) kd (1/s) KD(1) nM parental Human 6.19E+03 3.61E−05 5.83 germlined Human 7.09E+03 3.67E−05 5.17

Example 16 Production and Testing of Germlined Anti Tie1-E3-Fab for Binding to Recombinant Mouse Tie1 in BIAcore

Mouse Tie1-Fc antigen (0.5 mg/ml stock) was biotinylated using established procedures and after dilution 1/100 fold in HBS this was then used for capturing to a streptavidin chip. This was coated to a resonance value of 740 RU. All analysis was performed in HBS buffer. The parental Fab E3 0.587 mg/ml (11740 nM) was diluted 1/587 in HBS+BSA to obtain a stock of 20 nM and the germlined Fab E3 0.025 mg/ml (500 nM) was diluted 1/25 in HBS+BSA to obtain a stock of 20 nM. Serial dilutions were made of each Fab preparation to obtain 10 nM, 5 nM, 2.5 nM, and 1.25 nM. For the association phase samples were injected at 30 μl/min for 4 minutes using kinject program. This was followed by a 10 minutes dissociation phase, any remaining sample was stripped from the Tie-1 Fc surface at a flow of 50 μl/min with a single injection of 50 mM NaOH+1 M NaCl for 18 seconds. All samples were run and analyzed in duplicate.

Sensorgrams were analyzed using the simultaneous ka/kd fitting program with 1:1 model in the BIAEVALUATION™ software 3.1. The germlining of the E3 antibody has had minimal effect on the binding activity of the antibody.

TABLE 7 Comparison of the binding affinity of parental and germlined E3 Fab E3 Fab Tie-1 Fc ka (1/Ms) kd (1/s) KD(1) nM parental Mouse 2.46E+05 9.50E−04 3.9 germlined Mouse 3.40E+05 1.04E−03 3.1

Example 17 Comparison of Affinity of Germlined Anti Tie1 E3-IgG to Parental Anti Tie1 E3 for Binding to Recombinant Mouse Tie1 Using BIAcore

In order to evaluate if the binding behavior had been affected in any way by the conversion of the somatic mutations back to germline, the germlined antibody was produced and tested as a IgG. The germlined E3 was reformatted to an IgG as described. This was then used to transiently transfect HEK293T cells using established procedures. The IgG was purified from the culture supernatant using protein A column chromatography using established procedures and the subsequent IgG was then tested for binding activity using surface plasmon resonance (BIAcore). The germlined E3 IgG1 stock solution 0.63 mg/ml (2146-002) was diluted 1/50 in a buffer of pH 4.5 and the parental E3 IgG1 stock solution 0.56 mg/ml (2143-001) was diluted 1/50 in a buffer of pH 4.5. The IgG were directly coated via onto a CM5 chip. The surface of the chips was activated with a 7 minute pulse of 0.05M NHS/0.2M EDC and the IgG was flowed over until 780 RU germlined E3-IgG and 728 non germlined E3 IgG was coated onto the surface. All flow cells were subsequently deactivated with a 7 minute pulse of 1M ethanolamine hydrochloride pH8.5. All analysis was performed in HBS buffer. Purified recombinant mouse Tie-1 Fc was diluted 1/6.5 in HBS to obtain a 400 nM stock solution. Serial dilutions were made to obtain 200 nM, 100 nM, 50 nM and 25 nM Tie-1 Fc stocks. For analysis of the association phase samples were injected at 30 μl/min for 8.3 minutes using kinject program. This was followed by a 40 minutes dissociation phase. Any antigen remaining associated to the surface was stripped from the IgG surface at a flow of 50 μl/min with two injections of 10 mM glycine pH 1.5 for 30 seconds. All samples were run and analyzed in duplicate

Sensorgrams were analyzed using the simultaneous ka/kd fitting program with 1:1 model in the BIAEVALUATION™ software 3.1. The germlining process had minimal impact on the binding activity of the E3 IgG with respect to mouse Tie1-Fc.

TABLE 8 Comparison of the binding affinity of parental and germlined E3 IgG E3 IgG Tie-1 Fc ka (1/Ms) kd (1/s) KD(1) nM parental Mouse 6.17E+03 9.20E−05 14.9 germlined Mouse 6.00E+03 8.99E−05 15

Example 18 Comparison of IC₅₀ of Germlined Anti Tie1-E3 and Parental Anti Tie1—E3 in Tube Formation Assays Using HUVECS

Germlined E3 and its parental antibody were evaluated in the tube formation assay in a collagen type-I matrix. Human Umbilical vein endothelial cells (HUVEC) (freshly isolated) were obtained by treating human umbilical cord veins with Trypsin-EDTA (1×) (Gibco/Invitrogen) for 20-25 minutes at 37° C. The cells were then cultured in a T-25 flask coated with attachment factor (AF), (Cascade Biologics) in RPMI 1640 medium supplemented with 10% FCS, 0.4% BBE, 1% 1-glutamin, 1% penicillin/streptomycin. Primary cultures were detached with warm Trypsin-EDTA and used when confluent at the second or third passage. During culturing, the cells were kept in a proliferative state by culturing them in a split ratio 1:2 at an approximate density of the monolayer of about 60-80%. HUVEC monolayers were treated with trypsin/EDTA (500 μl/dish) at 37° C. for 3 min. Trypsin activity was stopped by adding 3 volumes of complete RPMI medium. The cells were carefully scraped, separated by repeated pipetting, and finally washed with PBS. HUVECs (passage 2) were seeded in their culture medium (40.10³/50 μl/well of a 96-well plate) on a collagen gel (50 μl of coll I 1.5 mg/ml) prepared by mixing 7.5 volumes of 2 mg/ml collagen (Collagen R; Serva, Heidelberg, Germany), 1 volume of 10×MEM, 1.5 volume of NaHCO3 (15.6 mg/ml) and ˜1 volume of NaOH to adjust the pH to 7.4. After 1 h 30, the culture medium was then discarded and the cells were covered with a new layer of collagen (1.5 mg/ml, new preparation, 50 μl/well). After polymerization of the gel, culture medium was added to each well in presence or in absence of E3 antibody or germlined E3 antibody (0.1 ng/ml to 100 ng/ml). The total length of the tube network on the culture surface was quantified at 40× magnification by the Metavue Software (Universal Imaging Corporation). Results from triplicate wells were expressed as mean vessel area per field±SEM (relative units). Each assay was performed at least three times (FIG. 16, FIG. 17). The conclusions are that conversion of the 3 somatic mutations to germline amino acids in E3 has had little effect on the potency of E3. Both parental E3 and germlined E3 inhibit tube formation in vitro with an essentially identical IC₅₀=10 ng/ml, i.e. 66 pM)

Example 19 Analysis of Germlined Anti Tie1-E3 in Tube Formation Assays with Mouse Endothelial Cells

In order to assess mouse Tie-1 cross-reactivity and biological activity on mouse Tie1, both E3 and germlined E3 were evaluated for their ability to inhibit tube formation in vitro using mouse endothelial cell line (LEII).

LEII lung mouse endothelial cell line (ATCC) was cultured in a T-25 flask in MEM medium with GLUTAMAX™ (Life Technologies Ltd., Paisley, Scotland) supplemented with 10% FCS, and 1% penicillin/streptomycin. During culturing, the cells were kept in a proliferative state by culturing them in a split ratio 1:5 at an approximate density of the monolayer of about 80%. LEII monolayers were treated with trypsin/EDTA (500 μl/dish) at 37° C. for 3 min. Trypsin activity was stopped by adding 3 volumes of complete MEM medium. The cells were carefully scraped, separated by repeated pipetting, and finally washed with PBS.LEII cells were seeded in their culture medium (20-40×10³/50 μl/well of a 96-well plate) on a basement membrane (BIOCOAT™ Angiogenesis System; Becton Dickinson). After polymerization of the MATRIGEL™ (30 min at 37° C., 5% CO₂ environment) the endothelial cell suspension resuspended in complete culture medium in the presence of the desired molecules (4.10⁵ cells/ml; 50 μl/well) was added to each well. The angiogenesis assay plate was then incubated for 16 to 18 hours at 37° C., 5% CO₂ atmosphere. The total length of the tube network was then quantified at 40× magnification by the METAVUE™ Software (Universal Imaging Corporation). Results from triplicate wells were expressed as mean vessel area per field±SEM (relative units). Each assay was performed at least two times. Germlined E3 is a potent inhibitor of tube formation in mouse endothelial cells.

Example 20 Immunohistochemical Analysis of Mouse Tumor Tissue Sections Using Anti Tie1-E3

We determined if antibody E3 binds to mouse endothelial cells in mouse xenographs. Immunohistochemistry was performed with biotinylated antibody E3 and control antibodies anti-CD31 (endothelial cell specific marker) and anti-PCNA (proliferating cell nuclear antigen). Formalin-fixed tumor tissues from a mouse-xenograph containing SW480 cells (ATCC) were tested for the binding pattern of the human anti-Tie1 antibody E3. 5 μm sections of paraffin embedded tissues were deparaffinized, rehydrated and pretreated with warm the citrate buffer (0.01 M sodium citrate, pH6 at 95° C.) for 45 min. The slides were cooled down in fresh citrate buffer for 20 min and rinsed with distilled water. The slides were hydrogen peroxide treated, (0.3% H₂O₂ in PBS), and preincubated with PBS, 5% FCS, 5% heat inactivated human serum (HS) for 1 hour. Between antibody incubations slides were washed 3 times 5 minutes in PBS. Biotinylated antibodies E3 and A2 were diluted to a concentration of 10 μg/ml in PBS, 10% HS and incubated for 1 hour at RT. Slides were then incubated with an avidin-HRP (Dako) for 30 minutes at room temperature. Staining was detected by AEC (Vector Laboratories, Burlingame) and H₂O₂. The peroxidase reaction was stopped with water and slides were counter-stained with haematoxylin. The tissues were evaluated for their binding reactivity. The staining pattern was consistent with staining of mouse endothelial cell Tie-1 and also with Tie1 expressed by the E3 binds to Tie-1 expressed by SW480 tumor cells in a mouse xenograft. 

1. An isolated protein comprising a heavy chain immunoglobulin variable domain sequence and a light chain immunoglobulin variable domain sequence, wherein the protein binds to Tie1 ectodomain and the heavy chain immunoglobulin variable domain sequence comprises one or more of the following properties: i) a HC CDR1 that includes an amino acid sequence as follows: (SEQ ID NO:117) (AGSR)-Y-(GVK)-M-(GSVF), (SEQ ID NO:118) (AGSIMRH)-Y-(GVMK)-M-(GSVMFH), or (SEQ ID NO:119) (AGSIMRNH)-Y-(AGTVMKPQ)-M-(AGSTVMYWFKH);

ii) a HC CDR2 that includes an amino acid sequence as follows: (SEQ ID NO:120) X-I-Y-P-S-G-G-X-T-X-Y-A-D-S-V-K-G, wherein X is any amino acid, (SEQ ID NO:121) (GSV)-I-(SY)-P-S-G-G-(WQ)-T-(GY), (SEQ ID NO:160) (GSV)-I-(SY)-P-S-G-G-(WNQ)-T-(GY), (SEQ ID NO:122) (GSV)-I-(SY)-P-S-G-G-(WQ)-T-(GY)-Y-A-D-S-V-K-G, or (SEQ ID NO:123) (GSVW)-I-(SY)-P-S-G-G-(AGVMYWPQH)-T-(AGSTLVMYFKH); iii) a HC CDR3 that includes an amino acid sequence as follows: (SEQ ID NO:124) V-(four or five residues)-F-D-(I/Y), (SEQ ID NO:125) G-Y-G-P-I-A-P-G-L-D-Y, (SEQ ID NO:126) (GV)-N-Y-Y-(GYD)-S-(SD)-G-Y-G-P-I-A-P-G-L-D-Y, (SEQ ID NO:127) (GVD)-(AGLN)-(LYR)-(GSTLYH)-(GYD)-(AGSYFP)-(SFD)- (AGYD)-(IY)-(GFD)-(YDP)-(IP)-A-P-G-L-D-Y, or (SEQ ID NO:128) VNYYDSSGYGPIAPGLDY.


2. The protein of claim 1 wherein the light chain immunoglobulin variable domain sequence comprises one or more of the following properties i) a LC CDR1 that includes an amino acid sequence as follows: (SEQ ID NO:129) R-A-S-Q-S-(IV)-S-(SR)-X1-Y-L-(AN), (SEQ ID NO:130) R-A-S-Q-S-V-S-S-X-L, (SEQ ID NO:131) R-A-S-Q-S-(IV)-S-(SR)-(SY)-(LY)-(ALN), or R-A-S-(REQ)-(GSTRN)-(IV)-(GSTIRN)-(STIRH)-X1- (SYWNH)-(LV)-(ASN)

(SEQ ID NO:132), wherein X1 can be serine or absent; ii) a LC CDR2 that includes an amino acid sequence as follows: X-A-S-X-R-A-T (SEQ ID NO:133), wherein X can be any amino acid, (AGD)-A-S-(STN)-R-A-T (SEQ ID NO:134), (AGD)-A-S-(STN)-(LR)-(AEQ)-(ST) (SEQ ID NO:135), or (AGTKDEH)-A-S-(STN)-(LR)-(AVEQ)-(ST) (SEQ ID NO:136); and iii) a LC CDR3 that includes an amino acid sequence as follows: (SEQ ID NO:137) Q-Q-(SYFR)-(GSYN)-S-(STYW)-(RP)-(LWR)-(TIY)-T, (SEQ ID NO:161) Q-Q-(SYFR)-(GSYN)-S-(STYW)-(RP)-(LWRH)-(TIY), (SEQ ID NO:138) (LQ)-Q-(SYFR)-(GSYN)-(SKN)-(STYW)-(RP)-(LWR)- (TIY)-T, (SEQ ID NO:139) Q-Q-(YR)-(GS)-S-(SW)-P-R-X1-T, wherein X1 is any amino acid or absent, (SEQ ID NO:140) (LQ)-(LQ)-(SYFRD)-(GSYN)-(STRKN)-(STYWF)-(RP)- (ILMWRH)-(TIY)-(TI), and (SEQ ID NO:141) (LQ)-(LRQ)-(SYFRD)-(GSYN)-(ASTRKN)-(STYWF)-(SVRP)- (STILMWRH)-(TIY)-(STI).


3. The protein of claim 1 wherein the light chain immunoglobulin variable domain sequence comprises one or more of the following properties i) a LC CDR1 that includes an amino acid sequence as follows: (SEQ ID NO:142) S-X-(ND)-(IV)-(AG)-X1-X2-X3, or (SEQ ID NO:143) T-(GR)-(ST)-S-X5-(ND)-(IV)-(AG)-X1-X2-X3-Y-X4-S,

wherein X1 is any amino acid (e.g., G or R), X2 is any amino acid (e.g., Y or N), X3 is any amino acid (e.g., F, N, or K), X4 is any amino acid (e.g., aliphatic, e.g., V or A); ii) a LC CDR2 that includes an amino acid sequence as follows: (DE)-V-N-N-R-P-S (SEQ ID NO:144), or (DE)-(VD)-(STDN)-(YRDN)-R-P-S (SEQ ID NO:145); and iii) a LC CDR3 that includes an amino acid sequence as follows: (SEQ ID NO:146) (SQ)-S-(SY)-(ASID)-(GSR)-(ST)-(STRN)-(STYR)- (ATLY)-(SVWQ).


4. The protein of claim 1 wherein the HC variable domain sequence comprises SEQ ID NO:118 and SEQ ID NO:160.
 5. The protein of claim 1 wherein the LC variable domain sequence comprises SEQ ID NO:132, SEQ ID NO:136, and SEQ ID NO:161.
 6. The protein of claim 1 wherein the amino acid sequence of the HC variable domain sequence is at least 85% identical to the amino acid sequence of the HC variable domain of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.
 7. The protein of claim 1 wherein the amino acid sequence of the LC variable domain sequence is at least 85% identical to the amino acid sequence of the LC variable domain of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4.
 8. The protein of claim 1 wherein the amino acid sequences of the HC variable domain sequence comprises CDR1, CDR2, and CDR3 sequences from the E3 clone, and the LC variable domain sequence comprises CDR1, CDR2, and CDR3 sequences from the E3 clone.
 9. The protein of claim 8 wherein the LC variable domain sequence comprises SEQ ID NO:159.
 10. The protein of claim 8 wherein the HC variable domain sequence comprises SEQ ID NO:114.
 11. The protein of claim 1 wherein the HC and LC framework regions are human.
 12. The protein of claim 1 further comprising an Fc domain.
 13. The protein of claim 12 that comprises the constant domains of a human IgG1, IgG2, IgG3, or IgG4.
 14. An isolated protein comprising a heavy chain immunoglobulin variable domain sequence and a light chain immunoglobulin variable domain sequence, wherein the protein binds to a Tie1 ectodomain and to endothelial cells, but does not substantially bind to platelets.
 15. The protein of claim 14 that binds to Tie1 with a K_(d) of less than 5 nM.
 16. The isolated protein of claim 14 that comprises the HC and LC immunoglobulin variable domains of the E3 antibody or domains that are at least 85% identical to the HC and LC immunoglobulin variable domains of the E3 antibody, respectively.
 17. The protein of claim 14 that inhibits tube formation by HUVEC cells in vitro.
 18. The protein of claim 14 that recognizes melanoma-associated structures in a histological section.
 19. An isolated protein comprising a heavy chain immunoglobulin variable domain sequence and a light chain immunoglobulin variable domain sequence, wherein the protein binds to a Tie1 ectodomain and competes with E3 for binding to Tie1 or binds to an epitope that overlaps an epitope that is recognized by E3 or that has at least one, two or three residues in common with an epitope that is recognized by E3.
 20. An isolated nucleic acid comprising a coding sequence that encodes a polypeptide comprising an immunoglobulin HC variable domain sequence, wherein the coding sequence is at least 85% identical to a reference sequence that encodes the HC variable domain of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4, or the coding sequence hybridizes to the reference sequence or a complement thereof.
 21. The nucleic acid of claim 20 that further comprises a second coding sequence that encodes a polypeptide comprising an immunoglobulin LC variable domain.
 22. An isolated nucleic acid comprising a coding sequence that encodes a polypeptide comprising an immunoglobulin LC variable domain sequence, wherein the coding sequence is at least 85% identical to a reference sequence that encodes the LC variable domain of clone E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, or s-H4, or the coding sequence hybridizes to the reference sequence or a complement thereof.
 23. The nucleic acid of claim 22 that further comprises a second coding sequence that encodes a polypeptide comprising an immunoglobulin HC variable domain.
 24. A host cell that contains a first nucleic acid sequence encoding a polypeptide comprising a HC variable domain of an antibody and a second nucleic acid sequence encoding a polypeptide comprising a LC variable domain of the antibody, wherein the antibody is a protein according to claim 1 or
 14. 25. A host cell that contains a first nucleic acid encoding a polypeptide comprising a HC variable region and a second nucleic acid encoding a polypeptide comprising a LC variable region, wherein the HC and the LC variable regions each comprise a sequence at least 85% identical to respective amino acid sequences of the HC and LC variable domains of a clone selected from the group consisting of E3, G2, p-A1, p-A10, p-B1, p-B3, p-C6, p-D12, p-F3, p-F4, p-G3, s-A10, s-H1, s-A2, s-B2, s-B9, s-C10, s-C2, s-C7, s-D11, s-E11, s-G10, and s-H4.
 26. A pharmaceutical composition comprising a protein of any of claims 1-19 and a pharmaceutically acceptable carrier.
 27. A method of modulating angiogenesis, the method comprising: administering a composition that comprises the protein of claim 1 or 14 to a subject in an amount effective to modulate angiogenesis in the subject.
 28. The method of claim 27 wherein the protein antagonizes Tie1 activity.
 29. The method of claim 27 wherein the subject has an angiogenesis-related disorder.
 30. The method of claim 27 wherein the subject has a neoplastic disorder.
 31. The method of claim 27 wherein the subject has a metastatic cancer.
 32. The method of claim 27 wherein the subject has an angiogenesis-dependent cancer or tumor.
 33. The method of claim 27 wherein the subject has an inflammatory disorder.
 34. The method of claim 33 wherein the subject has rheumatoid arthritis.
 35. The method of claim 33 wherein the subject has psoriasis.
 36. The method of claim 27 wherein the protein is delivered systemically.
 37. The method of claim 27 wherein the protein is administered in an amount effective to reduce one or more of the following activities: sprouting, splitting and remodeling of blood vessels.
 38. The method of claim 27 wherein the protein is administered in an amount effective to reduce vasculogenesis or tubule formation.
 39. A method of modulating endothelial cell activity in the subject, the method comprising: administering a composition that comprises the protein of claim 14 to a subject in an amount effective to modulate endothelial cell activity in the subject.
 40. A method for detecting the presence of a Tie1 protein, in a sample, in vitro, the method comprising: (i) contacting the sample with an Tie1-binding protein according to claim 1, under conditions that allow interaction of the Tie1-binding protein and the Tie1 protein to occur; and (ii) detecting formation of a complex between the Tie1-binding protein and the sample.
 41. A method for detecting the presence of Tie1 in vivo, the method comprising: (i) administering to a human subject an Tie1-binding protein, under conditions that allow interaction of the Tie1-binding ligand and the Tie1 protein to occur; and (ii) detecting formation of a complex between the Tie1-binding protein and a Tie1 molecule of the subject or detecting distribution of Tie1-binding protein or at least one location of the Tie1-binding protein in the subject. 